rw_semaphore is a sizable structure of 40 bytes and consumes considerable
space for each vm_area_struct. However vma_lock has two important
specifics which can be used to replace rw_semaphore with a simpler
structure:
1. Readers never wait. They try to take the vma_lock and fall back to
mmap_lock if that fails.
2. Only one writer at a time will ever try to write-lock a vma_lock
because writers first take mmap_lock in write mode. Because of these
requirements, full rw_semaphore functionality is not needed and we can
replace rw_semaphore and the vma->detached flag with a refcount
(vm_refcnt).
When vma is in detached state, vm_refcnt is 0 and only a call to
vma_mark_attached() can take it out of this state. Note that unlike
before, now we enforce both vma_mark_attached() and vma_mark_detached() to
be done only after vma has been write-locked. vma_mark_attached() changes
vm_refcnt to 1 to indicate that it has been attached to the vma tree.
When a reader takes read lock, it increments vm_refcnt, unless the top
usable bit of vm_refcnt (0x40000000) is set, indicating presence of a
writer. When writer takes write lock, it sets the top usable bit to
indicate its presence. If there are readers, writer will wait using newly
introduced mm->vma_writer_wait. Since all writers take mmap_lock in write
mode first, there can be only one writer at a time. The last reader to
release the lock will signal the writer to wake up. refcount might
overflow if there are many competing readers, in which case read-locking
will fail. Readers are expected to handle such failures.
In summary:
1. all readers increment the vm_refcnt;
2. writer sets top usable (writer) bit of vm_refcnt;
3. readers cannot increment the vm_refcnt if the writer bit is set;
4. in the presence of readers, writer must wait for the vm_refcnt to drop
to 1 (plus the VMA_LOCK_OFFSET writer bit), indicating an attached vma
with no readers;
5. vm_refcnt overflow is handled by the readers.
While this vm_lock replacement does not yet result in a smaller
vm_area_struct (it stays at 256 bytes due to cacheline alignment), it
allows for further size optimization by structure member regrouping to
bring the size of vm_area_struct below 192 bytes.
[surenb@google.com: fix a crash due to vma_end_read() that should have been removed]
Link: https://lkml.kernel.org/r/20250220200208.323769-1-surenb@google.com
Link: https://lkml.kernel.org/r/20250213224655.1680278-13-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Suggested-by: Matthew Wilcox <willy@infradead.org>
Tested-by: Shivank Garg <shivankg@amd.com>
Link: https://lkml.kernel.org/r/5e19ec93-8307-47c2-bb13-3ddf7150624e@amd.com
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Klara Modin <klarasmodin@gmail.com>
Cc: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Lokesh Gidra <lokeshgidra@google.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: "Paul E . McKenney" <paulmck@kernel.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Sourav Panda <souravpanda@google.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Will Deacon <will@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Extend the guard region self tests to explicitly assert that guard regions
work correctly for functionality specific to file-backed and shmem
mappings.
In addition to testing all of the existing guard region functionality that
is currently tested against anonymous mappings against file-backed and
shmem mappings (except those which are exclusive to anonymous mapping), we
now also:
* Test that MADV_SEQUENTIAL does not cause unexpected readahead behaviour.
* Test that MAP_PRIVATE behaves as expected with guard regions installed in
both a shared and private mapping of an fd.
* Test that a read-only file can correctly establish guard regions.
* Test a probable fault-around case does not interfere with guard regions
(or vice-versa).
* Test that truncation does not eliminate guard regions.
* Test that hole punching functions as expected in the presence of guard
regions.
* Test that a read-only mapping of a memfd write sealed mapping can have
guard regions established within it and function correctly without
violation of the seal.
* Test that guard regions installed into a mapping of the anonymous zero
page function correctly.
Link: https://lkml.kernel.org/r/90c16bec5fcaafcd1700dfa3e9988c3e1aa9ac1d.1739469950.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: "Paul E . McKenney" <paulmck@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Extend the guard region tests to allow for test fixture variants for anon,
shmem, and local file files.
This allows us to assert that each of the expected behaviours of anonymous
memory also applies correctly to file-backed (both shmem and an a file
created locally in the current working directory) and thus asserts the
same correctness guarantees as all the remaining tests do.
The fixture teardown is now performed in the parent process rather than
child forked ones, meaning cleanup is always performed, including
unlinking any generated temporary files.
Additionally the variant fixture data type now contains an enum value
indicating the type of backing store and the mmap() invocation is
abstracted to allow for the mapping of whichever backing store the variant
is testing.
We adjust tests as necessary to account for the fact they may now
reference files rather than anonymous memory.
Link: https://lkml.kernel.org/r/ab42228d2bd9b8aa18e9faebcd5c88732a7e5820.1739469950.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: "Paul E . McKenney" <paulmck@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Currently the mm selftests refuse to run if huge pages are not available
in the current system but this is an optional feature and not all the
tests actually require them. Change the test during startup to be
non-fatal and skip or omit tests which actually rely on having huge pages,
allowing the other tests to be run.
The gup_test does support using madvise() to configure huge pages but it
ignores the error code so we just let it run.
Link: https://lkml.kernel.org/r/20250212-kselftest-mm-no-hugepages-v1-2-44702f538522@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Nico Pache <npache@redhat.com>
Cc: Mariano Pache <npache@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The thuge-gen test_mmap() and test_shmget() tests are repeatedly run for a
variety of sizes but always report the result of their test with the same
name, meaning that automated sysetms running the tests are unable to
distinguish between the various tests. Add the supplied sizes to the
logged test names to distinguish between runs.
My test automation was getting pretty confused about what was going on
- the test names are a pretty important external interface.
Link: https://lkml.kernel.org/r/20250204-kselftest-mm-fix-dups-v1-1-6afe417ef4bb@kernel.org
Fixes: b38bd9b2c4 ("selftests/mm: thuge-gen: conform to TAP format output")
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Dev Jain <dev.jain@arm.com>
Cc: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The adj_start calculation has been a constant source of confusion in the
VMA merge code.
There are two cases to consider, one where we adjust the start of the
vmg->middle VMA (i.e. the vmg->__adjust_middle_start merge flag is set),
in which case adj_start is calculated as:
(1) adj_start = vmg->end - vmg->middle->vm_start
And the case where we adjust the start of the vmg->next VMA (i.e. the
vmg->__adjust_next_start merge flag is set), in which case adj_start is
calculated as:
(2) adj_start = -(vmg->middle->vm_end - vmg->end)
We apply (1) thusly:
vmg->middle->vm_start =
vmg->middle->vm_start + vmg->end - vmg->middle->vm_start
Which simplifies to:
vmg->middle->vm_start = vmg->end
Similarly, we apply (2) as:
vmg->next->vm_start =
vmg->next->vm_start + -(vmg->middle->vm_end - vmg->end)
Noting that for these VMAs to be mergeable vmg->middle->vm_end ==
vmg->next->vm_start and so this simplifies to:
vmg->next->vm_start =
vmg->next->vm_start + -(vmg->next->vm_start - vmg->end)
Which simplifies to:
vmg->next->vm_start = vmg->end
Therefore in each case, we simply need to adjust the start of the VMA to
vmg->end (!) and can do away with this adj_start calculation. The only
caveat is that we must ensure we update the vm_pgoff field correctly.
We therefore abstract this entire calculation to a new function
vmg_adjust_set_range() which performs this calculation and sets the
adjusted VMA's new range using the general vma_set_range() function.
We also must update vma_adjust_trans_huge() which expects the
now-abstracted adj_start parameter. It turns out this is wholly
unnecessary.
In vma_adjust_trans_huge() the relevant code is:
if (adjust_next > 0) {
struct vm_area_struct *next = find_vma(vma->vm_mm, vma->vm_end);
unsigned long nstart = next->vm_start;
nstart += adjust_next;
split_huge_pmd_if_needed(next, nstart);
}
The only case where this is relevant is when vmg->__adjust_middle_start is
specified (in which case adj_next would have been positive), i.e. the one
in which the vma specified is vmg->prev and this the sought 'next' VMA
would be vmg->middle.
We can therefore eliminate the find_vma() invocation altogether and simply
provide the vmg->middle VMA in this instance, or NULL otherwise.
Again we have an adj_next offset calculation:
next->vm_start + vmg->end - vmg->middle->vm_start
Where next == vmg->middle this simplifies to vmg->end as previously
demonstrated.
Therefore nstart is equal to vmg->end, which is already passed to
vma_adjust_trans_huge() via the 'end' parameter and so this code (rather
delightfully) simplifies to:
if (next)
split_huge_pmd_if_needed(next, end);
With these changes in place, it becomes silly for commit_merge() to return
vmg->target, as it is always the same and threaded through vmg, so we
finally change commit_merge() to return an error value once again.
This patch has no change in functional behaviour.
Link: https://lkml.kernel.org/r/7bce2cd4b5afb56211822835d145471280c3dccc.1738326519.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Introduce internal vmg->__adjust_middle_start and vmg->__adjust_next_start
merge flags, enabling us to indicate to commit_merge() that we are
performing a merge which either spans only part of vmg->middle, or part of
vmg->next respectively.
In the former instance, we change the start of vmg->middle to match the
attributes of vmg->prev, without spanning all of vmg->middle.
This implies that vmg->prev->vm_end and vmg->middle->vm_start are both
increased to form the new merged VMA (vmg->prev) and the new subsequent
VMA (vmg->middle).
In the latter case, we change the end of vmg->middle to match the
attributes of vmg->next, without spanning all of vmg->next.
This implies that vmg->middle->vm_end and vmg->next->vm_start are both
decreased to form the new merged VMA (vmg->next) and the new prior VMA
(vmg->middle).
Since we now have a stable set of prev, middle, next VMAs threaded through
vmg and with these flags set know what is happening, we can perform the
calculation in commit_merge() instead.
This allows us to drop the confusing adj_start parameter and instead pass
semantic information to commit_merge().
In the latter case the -(middle->vm_end - start) calculation becomes
-(middle->vm-end - vmg->end), however this is correct as vmg->end is set
to the start parameter.
This is because in this case (rather confusingly), we manipulate
vmg->middle, but ultimately return vmg->next, whose range will be
correctly specified. At this point vmg->start, end is the new range for
the prior VMA rather than the merged one.
This patch has no change in functional behaviour.
Link: https://lkml.kernel.org/r/bcec0cd980b373a5eb02236cb033034ce1effe42.1738326519.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The current VMA merge mechanism contains a number of confusing mechanisms
around removal of VMAs on merge and the shrinking of the VMA adjacent to
vma->target in the case of merges which result in a partial merge with
that adjacent VMA.
Since we now have a STABLE set of VMAs - prev, middle, next - we are now
able to have the caller of commit_merge() explicitly tell us which VMAs
need deleting, using newly introduced internal VMA merge flags.
Doing so allows us to embed this state within the VMG and remove the
confusing remove, remove2 parameters from commit_merge().
We additionally are able to eliminate the highly confusing and misleading
'expanded' parameter - a parameter that in reality refers to whether or
not the return VMA is the target one or the one immediately adjacent.
We can infer which is the case from whether or not the adj_start parameter
is negative. This also allows us to simplify further logic around
iterator configuration and VMA iterator stores.
Doing so means we can also eliminate the adjust parameter, as we are able
to infer which VMA ought to be adjusted from adj_start - a positive value
implies we adjust the start of 'middle', a negative one implies we adjust
the start of 'next'.
We are then able to have commit_merge() explicitly return the target VMA,
or NULL on inability to pre-allocate memory. Errors were previously
filtered so behaviour does not change.
We additionally move from the slightly odd use of a bitwise-flag enum
vmg->merge_flags field to vmg bitfields.
This patch has no change in functional behaviour.
Link: https://lkml.kernel.org/r/7bf2ed24af68aac18672b7acebbd9102f48c5b03.1738326519.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm: further simplify VMA merge operation", v3.
While significant efforts have been made to improve the VMA merge
operation, there remains remnants of the bad (or rather confusing) old
days, which make the code difficult to understand, more bug prone and thus
harder to modify.
This series attempts to significantly improve matters in a number of
respects - with a focus on simplifying the commit_merge() function which
actually actions the merge operation - and importantly, adjusting the two
most confusing merge cases - those in which we 'adjust' the VMA
immediately adjacent to the one being merged.
One source of confusion are the VMAs being threaded through the operation
themselves - vmg->prev, vmg->vma and vmg->next.
At the start of the operation, vmg->vma is either NULL if a new VMA is
propose to be added, or if not then a pointer to an existing VMA being
modified, and prev/next are (perhaps not present) VMAs sat immediately
before and after the range specified in vmg->start, end, respectively.
However, during the VMA merge operation, we change vmg->start, end and
pgoff to span the newly merged range and vmg->vma to either be:
a. The ultimately returned VMA (in most cases) or b. A VMA which we will
manipulate, but ultimately instead return vmg->next.
Case b. especially here is confusing for somebody reading this code, but
the fact we update this state, along with vmg->start, end, pgoff only
makes matters worse.
We simplify things by replacing vmg->vma with vmg->middle and never
changing it - this is always either NULL (for a new VMA) or the VMA being
modified between vmg->prev and vmg->next.
We further simplify by placing the merged VMA in a new vmg->target field -
whether case b. above is the case or not. The reader of the code can now
simply rely on vmg->middle being the middle VMA and vmg->target being the
ultimately merged VMA.
We additionally tackle the confusing cases where we 'adjust' VMAs other
than the one we ultimately return as the merged VMA (this includes case b.
above). These are:
(1)
merge
<----------->
|------||--------| |------------|---|
| prev || middle | -> | target | m |
|------||--------| |------------|---|
In which case middle must be adjusted so middle->vm_start is increased as
well as performing the merge.
(2) (equivalent to case b. above)
<------------->
|---------||------| |---|-------------|
| middle || next | -> | m | target |
|---------||------| |---|-------------|
In which case next must be adjusted so next->vm_start is decreased as well
as performing the merge.
This cases have previously been performed by calculating and passing
around a dubious and confusing 'adj_start' parameter along side a pointer
to an 'adjust' VMA indicating which VMA requires additional adjustment
(middle in case 1 and next in case 2).
With the VMG structure in place we are able to avoid this by simply
setting a merge flag to describe each case:
(1) Sets the vmg->__adjust_middle_start flag
(2) Sets the vmg->__adjust_next_start flag
By doing so it turns out we can vastly simplify the logic and calculate
what is required to perform the operation.
Taken together the refactorings make it far easier to understand what is
being done even in these more confusing cases, make the code far more
maintainable, debuggable, and testable, providing more internal state
indicating what is happening in the merge operation.
The changes have no functional net impact on the merge operation and
everything should still behave as it did before.
This patch (of 5):
The merge code, while much improved, still has a number of points of
confusion. As part of a broader series cleaning this up to make this more
maintainable, we start by addressing some confusion around
vma_merge_struct fields.
So far, the caller either provides no vmg->vma (a new VMA) or supplies the
existing VMA which is being altered, setting vmg->start,end,pgoff to the
proposed VMA dimensions.
vmg->vma is then updated, as are vmg->start,end,pgoff as the merge process
proceeds and the appropriate merge strategy is determined.
This is rather confusing, as vmg->vma starts off as the 'middle' VMA
between vmg->prev,next, but becomes the 'target' VMA, except in one
specific edge case (merge next, shrink middle).
Int his patch we introduce vmg->middle to describe the VMA that is between
vmg->prev and vmg->next, and does NOT change during the merge operation.
We replace vmg->vma with vmg->target, and use this only during the merge
operation itself.
Aside from the merge right, shrink middle case, this becomes the VMA that
forms the basis of the VMA that is returned. This edge case can be
addressed in a future commit.
We also add a number of comments to explain what is going on.
Finally, we adjust the ASCII diagrams showing each merge case in
vma_merge_existing_range() to be clearer - the arrow range previously
showed the vmg->start, end spanned area, but it is clearer to change this
to show the final merged VMA.
This patch has no change in functional behaviour.
Link: https://lkml.kernel.org/r/cover.1738326519.git.lorenzo.stoakes@oracle.com
Link: https://lkml.kernel.org/r/4dfe60f1419d55e5d0516f56349695d73a57184c.1738326519.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
We noticed that uffd-stress test was always failing to run when invoked
for the hugetlb profiles on x86_64 systems with a processor count of 64 or
bigger:
...
# ------------------------------------
# running ./uffd-stress hugetlb 128 32
# ------------------------------------
# ERROR: invalid MiB (errno=9, @uffd-stress.c:459)
...
# [FAIL]
not ok 3 uffd-stress hugetlb 128 32 # exit=1
...
The problem boils down to how run_vmtests.sh (mis)calculates the size of
the region it feeds to uffd-stress. The latter expects to see an amount
of MiB while the former is just giving out the number of free hugepages
halved down. This measurement discrepancy ends up violating uffd-stress'
assertion on number of hugetlb pages allocated per CPU, causing it to bail
out with the error above.
This commit fixes that issue by adjusting run_vmtests.sh's
half_ufd_size_MB calculation so it properly renders the region size in
MiB, as expected, while maintaining all of its original constraints in
place.
Link: https://lkml.kernel.org/r/20250218192251.53243-1-aquini@redhat.com
Fixes: 2e47a445d7 ("selftests/mm: run_vmtests.sh: fix hugetlb mem size calculation")
Signed-off-by: Rafael Aquini <raquini@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Pull KVM fixes from Paolo Bonzini:
"arm64:
- Fix a couple of bugs affecting pKVM's PSCI relay implementation
when running in the hVHE mode, resulting in the host being entered
with the MMU in an unknown state, and EL2 being in the wrong mode
x86:
- Set RFLAGS.IF in C code on SVM to get VMRUN out of the STI shadow
- Ensure DEBUGCTL is context switched on AMD to avoid running the
guest with the host's value, which can lead to unexpected bus lock
#DBs
- Suppress DEBUGCTL.BTF on AMD (to match Intel), as KVM doesn't
properly emulate BTF. KVM's lack of context switching has meant BTF
has always been broken to some extent
- Always save DR masks for SNP vCPUs if DebugSwap is *supported*, as
the guest can enable DebugSwap without KVM's knowledge
- Fix a bug in mmu_stress_tests where a vCPU could finish the "writes
to RO memory" phase without actually generating a write-protection
fault
- Fix a printf() goof in the SEV smoke test that causes build
failures with -Werror
- Explicitly zero EAX and EBX in CPUID.0x8000_0022 output when
PERFMON_V2 isn't supported by KVM"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
KVM: x86: Explicitly zero EAX and EBX when PERFMON_V2 isn't supported by KVM
KVM: selftests: Fix printf() format goof in SEV smoke test
KVM: selftests: Ensure all vCPUs hit -EFAULT during initial RO stage
KVM: SVM: Don't rely on DebugSwap to restore host DR0..DR3
KVM: SVM: Save host DR masks on CPUs with DebugSwap
KVM: arm64: Initialize SCTLR_EL1 in __kvm_hyp_init_cpu()
KVM: arm64: Initialize HCR_EL2.E2H early
KVM: x86: Snapshot the host's DEBUGCTL after disabling IRQs
KVM: SVM: Manually context switch DEBUGCTL if LBR virtualization is disabled
KVM: x86: Snapshot the host's DEBUGCTL in common x86
KVM: SVM: Suppress DEBUGCTL.BTF on AMD
KVM: SVM: Drop DEBUGCTL[5:2] from guest's effective value
KVM: selftests: Assert that STI blocking isn't set after event injection
KVM: SVM: Set RFLAGS.IF=1 in C code, to get VMRUN out of the STI shadow
KVM x86 fixes for 6.14-rcN #2
- Set RFLAGS.IF in C code on SVM to get VMRUN out of the STI shadow.
- Ensure DEBUGCTL is context switched on AMD to avoid running the guest with
the host's value, which can lead to unexpected bus lock #DBs.
- Suppress DEBUGCTL.BTF on AMD (to match Intel), as KVM doesn't properly
emulate BTF. KVM's lack of context switching has meant BTF has always been
broken to some extent.
- Always save DR masks for SNP vCPUs if DebugSwap is *supported*, as the guest
can enable DebugSwap without KVM's knowledge.
- Fix a bug in mmu_stress_tests where a vCPU could finish the "writes to RO
memory" phase without actually generating a write-protection fault.
- Fix a printf() goof in the SEV smoke test that causes build failures with
-Werror.
- Explicitly zero EAX and EBX in CPUID.0x8000_0022 output when PERFMON_V2
isn't supported by KVM.
Pull misc fixes from Andrew Morton:
"33 hotfixes. 24 are cc:stable and the remainder address post-6.13
issues or aren't considered necessary for -stable kernels.
26 are for MM and 7 are for non-MM.
- "mm: memory_failure: unmap poisoned folio during migrate properly"
from Ma Wupeng fixes a couple of two year old bugs involving the
migration of hwpoisoned folios.
- "selftests/damon: three fixes for false results" from SeongJae Park
fixes three one year old bugs in the SAMON selftest code.
The remainder are singletons and doubletons. Please see the individual
changelogs for details"
* tag 'mm-hotfixes-stable-2025-03-08-16-27' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (33 commits)
mm/page_alloc: fix uninitialized variable
rapidio: add check for rio_add_net() in rio_scan_alloc_net()
rapidio: fix an API misues when rio_add_net() fails
MAINTAINERS: .mailmap: update Sumit Garg's email address
Revert "mm/page_alloc.c: don't show protection in zone's ->lowmem_reserve[] for empty zone"
mm: fix finish_fault() handling for large folios
mm: don't skip arch_sync_kernel_mappings() in error paths
mm: shmem: remove unnecessary warning in shmem_writepage()
userfaultfd: fix PTE unmapping stack-allocated PTE copies
userfaultfd: do not block on locking a large folio with raised refcount
mm: zswap: use ATOMIC_LONG_INIT to initialize zswap_stored_pages
mm: shmem: fix potential data corruption during shmem swapin
mm: fix kernel BUG when userfaultfd_move encounters swapcache
selftests/damon/damon_nr_regions: sort collected regiosn before checking with min/max boundaries
selftests/damon/damon_nr_regions: set ops update for merge results check to 100ms
selftests/damon/damos_quota: make real expectation of quota exceeds
include/linux/log2.h: mark is_power_of_2() with __always_inline
NFS: fix nfs_release_folio() to not deadlock via kcompactd writeback
mm, swap: avoid BUG_ON in relocate_cluster()
mm: swap: use correct step in loop to wait all clusters in wait_for_allocation()
...
Pull s390 fixes from Vasily Gorbik:
- Fix return address recovery of traced function in ftrace to ensure
reliable stack unwinding
- Fix compiler warnings and runtime crashes of vDSO selftests on s390
by introducing a dedicated GNU hash bucket pointer with correct
32-bit entry size
- Fix test_monitor_call() inline asm, which misses CC clobber, by
switching to an instruction that doesn't modify CC
* tag 's390-6.14-6' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
s390/ftrace: Fix return address recovery of traced function
selftests/vDSO: Fix GNU hash table entry size for s390x
s390/traps: Fix test_monitor_call() inline assembly
damon_nr_regions.py starts DAMON, periodically collect number of regions
in snapshots, and see if it is in the requested range. The check code
assumes the numbers are sorted on the collection list, but there is no
such guarantee. Hence this can result in false positive test success.
Sort the list before doing the check.
Link: https://lkml.kernel.org/r/20250225222333.505646-4-sj@kernel.org
Fixes: 781497347d ("selftests/damon: implement test for min/max_nr_regions")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
damon_nr_regions.py updates max_nr_regions to a number smaller than
expected number of real regions and confirms DAMON respect the harsh
limit. To give time for DAMON to make changes for the regions, 3
aggregation intervals (300 milliseconds) are given.
The internal mechanism works with not only the max_nr_regions, but also
sz_limit, though. It avoids merging region if that casn make region of
size larger than sz_limit. In the test, sz_limit is set too small to
achive the new max_nr_regions, unless it is updated for the new
min_nr_regions. But the update is done only once per operations set
update interval, which is one second by default.
Hence, the test randomly incurs false positive failures. Fix it by
setting the ops interval same to aggregation interval, to make sure
sz_limit is updated by the time of the check.
Link: https://lkml.kernel.org/r/20250225222333.505646-3-sj@kernel.org
Fixes: 8bf890c816 ("selftests/damon/damon_nr_regions: test online-tuned max_nr_regions")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "selftests/damon: three fixes for false results".
Fix three DAMON selftest bugs that cause two and one false positive
failures and successes.
This patch (of 3):
damos_quota.py assumes the quota will always exceeded. But whether quota
will be exceeded or not depend on the monitoring results. Actually the
monitored workload has chaning access pattern and hence sometimes the
quota may not really be exceeded. As a result, false positive test
failures happen. Expect how much time the quota will be exceeded by
checking the monitoring results, and use it instead of the naive
assumption.
Link: https://lkml.kernel.org/r/20250225222333.505646-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20250225222333.505646-2-sj@kernel.org
Fixes: 51f58c9da1 ("selftests/damon: add a test for DAMOS quota")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
damos_quota_goal.py selftest see if DAMOS quota goals tuning feature
increases or reduces the effective size quota for given score as expected.
The tuning feature sets the minimum quota size as one byte, so if the
effective size quota is already one, we cannot expect it further be
reduced. However the test is not aware of the edge case, and fails since
it shown no expected change of the effective quota. Handle the case by
updating the failure logic for no change to see if it was the case, and
simply skips to next test input.
Link: https://lkml.kernel.org/r/20250217182304.45215-1-sj@kernel.org
Fixes: f1c07c0a16 ("selftests/damon: add a test for DAMOS quota goal")
Signed-off-by: SeongJae Park <sj@kernel.org>
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202502171423.b28a918d-lkp@intel.com
Cc: Shuah Khan <shuah@kernel.org>
Cc: <stable@vger.kernel.org> [6.10.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Commit 14be4e6f35 ("selftests: vDSO: fix ELF hash table entry size for s390x")
changed the type of the ELF hash table entries to 64bit on s390x.
However the *GNU* hash tables entries are always 32bit.
The "bucket" pointer is shared between both hash algorithms.
On s390, this caused the GNU hash algorithm to access its 32-bit entries as if they
were 64-bit, triggering compiler warnings (assignment between "Elf64_Xword *" and
"Elf64_Word *") and runtime crashes.
Introduce a new dedicated "gnu_bucket" pointer which is used by the GNU hash.
Fixes: e0746bde6f ("selftests/vDSO: support DT_GNU_HASH")
Reviewed-by: Jens Remus <jremus@linux.ibm.com>
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Acked-by: Shuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/20250217-selftests-vdso-s390-gnu-hash-v2-1-f6c2532ffe2a@linutronix.de
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Print out the index of mismatching XSAVE bytes using unsigned decimal
format. Some versions of clang complain about trying to print an integer
as an unsigned char.
x86/sev_smoke_test.c:55:51: error: format specifies type 'unsigned char'
but the argument has type 'int' [-Werror,-Wformat]
Fixes: 8c53183dba ("selftests: kvm: add test for transferring FPU state into VMSA")
Link: https://lore.kernel.org/r/20250228233852.3855676-1-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
During the initial mprotect(RO) stage of mmu_stress_test, keep vCPUs
spinning until all vCPUs have hit -EFAULT, i.e. until all vCPUs have tried
to write to a read-only page. If a vCPU manages to complete an entire
iteration of the loop without hitting a read-only page, *and* the vCPU
observes mprotect_ro_done before starting a second iteration, then the
vCPU will prematurely fall through to GUEST_SYNC(3) (on x86 and arm64) and
get out of sequence.
Replace the "do-while (!r)" loop around the associated _vcpu_run() with
a single invocation, as barring a KVM bug, the vCPU is guaranteed to hit
-EFAULT, and retrying on success is super confusion, hides KVM bugs, and
complicates this fix. The do-while loop was semi-unintentionally added
specifically to fudge around a KVM x86 bug, and said bug is unhittable
without modifying the test to force x86 down the !(x86||arm64) path.
On x86, if forced emulation is enabled, vcpu_arch_put_guest() may trigger
emulation of the store to memory. Due a (very, very) longstanding bug in
KVM x86's emulator, emulate writes to guest memory that fail during
__kvm_write_guest_page() unconditionally return KVM_EXIT_MMIO. While that
is desirable in the !memslot case, it's wrong in this case as the failure
happens due to __copy_to_user() hitting a read-only page, not an emulated
MMIO region.
But as above, x86 only uses vcpu_arch_put_guest() if the __x86_64__ guards
are clobbered to force x86 down the common path, and of course the
unexpected MMIO is a KVM bug, i.e. *should* cause a test failure.
Fixes: b6c304aec6 ("KVM: selftests: Verify KVM correctly handles mprotect(PROT_READ)")
Reported-by: Yan Zhao <yan.y.zhao@intel.com>
Closes: https://lore.kernel.org/all/20250208105318.16861-1-yan.y.zhao@intel.com
Debugged-by: Yan Zhao <yan.y.zhao@intel.com>
Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Tested-by: Yan Zhao <yan.y.zhao@intel.com>
Link: https://lore.kernel.org/r/20250228230804.3845860-1-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Pull tracing fixes from Steven Rostedt:
- Fix crash from bad histogram entry
An error path in the histogram creation could leave an entry in a
link list that gets freed. Then when a new entry is added it can
cause a u-a-f bug. This is fixed by restructuring the code so that
the histogram is consistent on failure and everything is cleaned up
appropriately.
- Fix fprobe self test
The fprobe self test relies on no function being attached by ftrace.
BPF programs can attach to functions via ftrace and systemd now does
so. This causes those functions to appear in the enabled_functions
list which holds all functions attached by ftrace. The selftest also
uses that file to see if functions are being connected correctly. It
counts the functions in the file, but if there's already functions in
the file, it fails. Instead, add the number of functions in the file
at the start of the test to all the calculations during the test.
- Fix potential division by zero of the function profiler stddev
The calculated divisor that calculates the standard deviation of the
function times can overflow. If the overflow happens to land on zero,
that can cause a division by zero. Check for zero from the
calculation before doing the division.
TODO: Catch when it ever overflows and report it accordingly. For
now, just prevent the system from crashing.
* tag 'trace-v6.14-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
ftrace: Avoid potential division by zero in function_stat_show()
selftests/ftrace: Let fprobe test consider already enabled functions
tracing: Fix bad hist from corrupting named_triggers list
Add an L1 (guest) assert to the nested exceptions test to verify that KVM
doesn't put VMRUN in an STI shadow (AMD CPUs bleed the shadow into the
guest's int_state if a #VMEXIT occurs before VMRUN fully completes).
Add a similar assert to the VMX side as well, because why not.
Reviewed-by: Jim Mattson <jmattson@google.com>
Link: https://lore.kernel.org/r/20250224165442.2338294-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
The fprobe test fails on Fedora 41 since the fprobe test assumption that
the number of enabled_functions is zero before the test starts is not
necessarily true. Some user space tools, like systemd, add BPF programs
that attach to functions. Those will show up in the enabled_functions table
and must be taken into account by the fprobe test.
Therefore count the number of lines of enabled_functions before tests
start, and use that as base when comparing expected results.
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Link: https://lore.kernel.org/20250226142703.910860-1-hca@linux.ibm.com
Fixes: e85c5e9792 ("selftests/ftrace: Update fprobe test to check enabled_functions file")
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Pull networking fixes from Jakub Kicinski:
"Including fixes from bluetooth.
We didn't get netfilter or wireless PRs this week, so next week's PR
is probably going to be bigger. A healthy dose of fixes for bugs
introduced in the current release nonetheless.
Current release - regressions:
- Bluetooth: always allow SCO packets for user channel
- af_unix: fix memory leak in unix_dgram_sendmsg()
- rxrpc:
- remove redundant peer->mtu_lock causing lockdep splats
- fix spinlock flavor issues with the peer record hash
- eth: iavf: fix circular lock dependency with netdev_lock
- net: use rtnl_net_dev_lock() in
register_netdevice_notifier_dev_net() RDMA driver register notifier
after the device
Current release - new code bugs:
- ethtool: fix ioctl confusing drivers about desired HDS user config
- eth: ixgbe: fix media cage present detection for E610 device
Previous releases - regressions:
- loopback: avoid sending IP packets without an Ethernet header
- mptcp: reset connection when MPTCP opts are dropped after join
Previous releases - always broken:
- net: better track kernel sockets lifetime
- ipv6: fix dst ref loop on input in seg6 and rpl lw tunnels
- phy: qca807x: use right value from DTS for DAC_DSP_BIAS_CURRENT
- eth: enetc: number of error handling fixes
- dsa: rtl8366rb: reshuffle the code to fix config / build issue with
LED support"
* tag 'net-6.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (53 commits)
net: ti: icss-iep: Reject perout generation request
idpf: fix checksums set in idpf_rx_rsc()
selftests: drv-net: Check if combined-count exists
net: ipv6: fix dst ref loop on input in rpl lwt
net: ipv6: fix dst ref loop on input in seg6 lwt
usbnet: gl620a: fix endpoint checking in genelink_bind()
net/mlx5: IRQ, Fix null string in debug print
net/mlx5: Restore missing trace event when enabling vport QoS
net/mlx5: Fix vport QoS cleanup on error
net: mvpp2: cls: Fixed Non IP flow, with vlan tag flow defination.
af_unix: Fix memory leak in unix_dgram_sendmsg()
net: Handle napi_schedule() calls from non-interrupt
net: Clear old fragment checksum value in napi_reuse_skb
gve: unlink old napi when stopping a queue using queue API
net: Use rtnl_net_dev_lock() in register_netdevice_notifier_dev_net().
tcp: Defer ts_recent changes until req is owned
net: enetc: fix the off-by-one issue in enetc_map_tx_tso_buffs()
net: enetc: remove the mm_lock from the ENETC v4 driver
net: enetc: add missing enetc4_link_deinit()
net: enetc: update UDP checksum when updating originTimestamp field
...
Some drivers, like tg3, do not set combined-count:
$ ethtool -l enp4s0f1
Channel parameters for enp4s0f1:
Pre-set maximums:
RX: 4
TX: 4
Other: n/a
Combined: n/a
Current hardware settings:
RX: 4
TX: 1
Other: n/a
Combined: n/a
In the case where combined-count is not set, the ethtool netlink code
in the kernel elides the value and the code in the test:
netnl.channels_get(...)
With a tg3 device, the returned dictionary looks like:
{'header': {'dev-index': 3, 'dev-name': 'enp4s0f1'},
'rx-max': 4,
'rx-count': 4,
'tx-max': 4,
'tx-count': 1}
Note that the key 'combined-count' is missing. As a result of this
missing key the test raises an exception:
# Exception| if channels['combined-count'] == 0:
# Exception| ~~~~~~~~^^^^^^^^^^^^^^^^^^
# Exception| KeyError: 'combined-count'
Change the test to check if 'combined-count' is a key in the dictionary
first and if not assume that this means the driver has separate RX and
TX queues.
With this change, the test now passes successfully on tg3 and mlx5
(which does have a 'combined-count').
Fixes: 1cf2704242 ("net: selftest: add test for netdev netlink queue-get API")
Signed-off-by: Joe Damato <jdamato@fastly.com>
Reviewed-by: David Wei <dw@davidwei.uk>
Link: https://patch.msgid.link/20250226181957.212189-1-jdamato@fastly.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Pull landlock fixes from Mickaël Salaün:
"Fixes to TCP socket identification, documentation, and tests"
* tag 'landlock-6.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/mic/linux:
selftests/landlock: Add binaries to .gitignore
selftests/landlock: Test that MPTCP actions are not restricted
selftests/landlock: Test TCP accesses with protocol=IPPROTO_TCP
landlock: Fix non-TCP sockets restriction
landlock: Minor typo and grammar fixes in IPC scoping documentation
landlock: Fix grammar error
selftests/landlock: Enable the new CONFIG_AF_UNIX_OOB
Pull perf tools fixes from Arnaldo Carvalho de Melo:
- Fix tools/ quiet build Makefile infrastructure that was broken when
working on tools/perf/ without testing on other tools/ living
utilities.
* tag 'perf-tools-fixes-for-v6.14-2-2025-02-25' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools:
tools: Remove redundant quiet setup
tools: Unify top-level quiet infrastructure
Pull RISC-V fixes from Palmer Dabbelt:
- A fix for cacheinfo DT probing to avoid reading non-boolean
properties as booleans.
- A fix for cpufeature to use bitmap_equal() instead of memcmp(), so
unused bits are ignored.
- Fixes for cmpxchg and futex cmpxchg that properly encode the sign
extension requirements on inline asm, which results in spurious
successes. This manifests in at least inode_set_ctime_current, but is
likely just a disaster waiting to happen.
- A fix for the rseq selftests, which was using an invalid constraint.
- A pair of fixes for signal frame size handling:
- We were reserving space for an extra empty extension context
header on systems with extended signal context, thus resulting in
unnecessarily large allocations.
- We weren't properly checking for available extensions before
calculating the signal stack size, which resulted in undersized
stack allocations on some systems (at least those with T-Head
custom vectors).
Also, we've added Alex as a reviewer. He's been helping out a ton
lately, thanks!
* tag 'riscv-for-linus-6.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
MAINTAINERS: Add myself as a riscv reviewer
riscv: signal: fix signal_minsigstksz
riscv: signal: fix signal frame size
rseq/selftests: Fix riscv rseq_offset_deref_addv inline asm
riscv/futex: sign extend compare value in atomic cmpxchg
riscv/atomic: Do proper sign extension also for unsigned in arch_cmpxchg
riscv: cpufeature: use bitmap_equal() instead of memcmp()
riscv: cacheinfo: Use of_property_present() for non-boolean properties
Test XDP and HDS interaction. While at it add a test for using the IOCTL,
as that turned out to be the real culprit.
Testing bnxt:
# NETIF=eth0 ./ksft-net-drv/drivers/net/hds.py
KTAP version 1
1..12
ok 1 hds.get_hds
ok 2 hds.get_hds_thresh
ok 3 hds.set_hds_disable # SKIP disabling of HDS not supported by the device
ok 4 hds.set_hds_enable
ok 5 hds.set_hds_thresh_zero
ok 6 hds.set_hds_thresh_max
ok 7 hds.set_hds_thresh_gt
ok 8 hds.set_xdp
ok 9 hds.enabled_set_xdp
ok 10 hds.ioctl
ok 11 hds.ioctl_set_xdp
ok 12 hds.ioctl_enabled_set_xdp
# Totals: pass:11 fail:0 xfail:0 xpass:0 skip:1 error:0
and netdevsim:
# ./ksft-net-drv/drivers/net/hds.py
KTAP version 1
1..12
ok 1 hds.get_hds
ok 2 hds.get_hds_thresh
ok 3 hds.set_hds_disable
ok 4 hds.set_hds_enable
ok 5 hds.set_hds_thresh_zero
ok 6 hds.set_hds_thresh_max
ok 7 hds.set_hds_thresh_gt
ok 8 hds.set_xdp
ok 9 hds.enabled_set_xdp
ok 10 hds.ioctl
ok 11 hds.ioctl_set_xdp
ok 12 hds.ioctl_enabled_set_xdp
# Totals: pass:12 fail:0 xfail:0 xpass:0 skip:0 error:0
Netdevsim needs a sane default for tx/rx ring size.
ethtool 6.11 is needed for the --disable-netlink option.
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Tested-by: Taehee Yoo <ap420073@gmail.com>
Link: https://patch.msgid.link/20250221025141.1132944-2-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Pull tracing fixes from Steven Rostedt:
"Function graph accounting fixes:
- Fix the manage ops hashes
The function graph registers a "manager ops" and "sub-ops" to
ftrace. The manager ops does not have any callback but calls the
sub-ops callbacks. The manage ops hashes (what is used to tell
ftrace what functions to attach to) is built on the sub-ops it
manages.
There was an error in the way it built the hash. An empty hash
means to attach to all functions. When the manager ops had one
sub-ops it properly copied its hash. But when the manager ops had
more than one sub-ops, it went into a loop to make a set of all
functions it needed to add to the hash. If any of the subops hashes
was empty, that would mean to attach to all functions. The error
was that the first iteration of the loop passed in an empty hash to
start with in order to add the other hashes. That starting hash was
mistaken as to attach to all functions. This made the manage ops
attach to all functions whenever it had two or more sub-ops, even
if each sub-op was attached to only a single function.
- Do not add duplicate entries to the manager ops hash
If two or more subops hashes trace the same function, an entry for
that function will be added to the manager ops for each subops.
This causes waste and extra overhead.
Fprobe accounting fixes:
- Remove last function from fprobe hash
Fprobes has a ftrace hash to manage which functions an fprobe is
attached to. It also has a counter of how many fprobes are
attached. When the last fprobe is removed, it unregisters the
fprobe from ftrace but does not remove the functions the last
fprobe was attached to from the hash. This leaves the old functions
attached. When a new fprobe is added, the fprobe infrastructure
attaches to not only the functions of the new fprobe, but also to
the functions of the last fprobe.
- Fix accounting of the fprobe counter
When a fprobe is added, it updates a counter. If the counter goes
from zero to one, it attaches its ops to ftrace. When an fprobe is
removed, the counter is decremented. If the counter goes from 1 to
zero, it removes the fprobes ops from ftrace.
There was an issue where if two fprobes trace the same function,
the addition of each fprobe would increment the counter. But when
removing the first of the fprobes, it would notice that another
fprobe is still attached to one of its functions no it does not
remove the functions from the ftrace ops.
But it also did not decrement the counter, so when the last fprobe
is removed, the counter is still one. This leaves the fprobes
callback still registered with ftrace and it being called by the
functions defined by the fprobes ops hash. Worse yet, because all
the functions from the fprobe ops hash have been removed, that
tells ftrace that it wants to trace all functions.
Thus, this puts the state of the system where every function is
calling the fprobe callback handler (which does nothing as there
are no registered fprobes), but this causes a good 13% slow down of
the entire system.
Other updates:
- Add a selftest to test the above issues to prevent regressions.
- Fix preempt count accounting in function tracing
Better recursion protection was added to function tracing which
added another layer of preempt disable. As the preempt_count gets
traced in the event, it needs to subtract the amount of preempt
disabling the tracer does to record what the preempt_count was when
the trace was triggered.
- Fix memory leak in output of set_event
A variable is passed by the seq_file functions in the location that
is set by the return of the next() function. The start() function
allocates it and the stop() function frees it. But when the last
item is found, the next() returns NULL which leaks the data that
was allocated in start(). The m->private is used for something
else, so have next() free the data when it returns NULL, as stop()
will then just receive NULL in that case"
* tag 'ftrace-v6.14-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracing: Fix memory leak when reading set_event file
ftrace: Correct preemption accounting for function tracing.
selftests/ftrace: Update fprobe test to check enabled_functions file
fprobe: Fix accounting of when to unregister from function graph
fprobe: Always unregister fgraph function from ops
ftrace: Do not add duplicate entries in subops manager ops
ftrace: Fix accounting of adding subops to a manager ops
A few bugs were found in the fprobe accounting logic along with it using
the function graph infrastructure. Update the fprobe selftest to catch
those bugs in case they or something similar shows up in the future.
The test now checks the enabled_functions file which shows all the
functions attached to ftrace or fgraph. When enabling a fprobe, make sure
that its corresponding function is also added to that file. Also add two
more fprobes to enable to make sure that the fprobe logic works properly
with multiple probes.
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Link: https://lore.kernel.org/20250220202055.733001756@goodmis.org
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Tested-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Pull BPF fixes from Daniel Borkmann:
- Fix a soft-lockup in BPF arena_map_free on 64k page size kernels
(Alan Maguire)
- Fix a missing allocation failure check in BPF verifier's
acquire_lock_state (Kumar Kartikeya Dwivedi)
- Fix a NULL-pointer dereference in trace_kfree_skb by adding kfree_skb
to the raw_tp_null_args set (Kuniyuki Iwashima)
- Fix a deadlock when freeing BPF cgroup storage (Abel Wu)
- Fix a syzbot-reported deadlock when holding BPF map's freeze_mutex
(Andrii Nakryiko)
- Fix a use-after-free issue in bpf_test_init when eth_skb_pkt_type is
accessing skb data not containing an Ethernet header (Shigeru
Yoshida)
- Fix skipping non-existing keys in generic_map_lookup_batch (Yan Zhai)
- Several BPF sockmap fixes to address incorrect TCP copied_seq
calculations, which prevented correct data reads from recv(2) in user
space (Jiayuan Chen)
- Two fixes for BPF map lookup nullness elision (Daniel Xu)
- Fix a NULL-pointer dereference from vmlinux BTF lookup in
bpf_sk_storage_tracing_allowed (Jared Kangas)
* tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
selftests: bpf: test batch lookup on array of maps with holes
bpf: skip non exist keys in generic_map_lookup_batch
bpf: Handle allocation failure in acquire_lock_state
bpf: verifier: Disambiguate get_constant_map_key() errors
bpf: selftests: Test constant key extraction on irrelevant maps
bpf: verifier: Do not extract constant map keys for irrelevant maps
bpf: Fix softlockup in arena_map_free on 64k page kernel
net: Add rx_skb of kfree_skb to raw_tp_null_args[].
bpf: Fix deadlock when freeing cgroup storage
selftests/bpf: Add strparser test for bpf
selftests/bpf: Fix invalid flag of recv()
bpf: Disable non stream socket for strparser
bpf: Fix wrong copied_seq calculation
strparser: Add read_sock callback
bpf: avoid holding freeze_mutex during mmap operation
bpf: unify VM_WRITE vs VM_MAYWRITE use in BPF map mmaping logic
selftests/bpf: Adjust data size to have ETH_HLEN
bpf, test_run: Fix use-after-free issue in eth_skb_pkt_type()
bpf: Remove unnecessary BTF lookups in bpf_sk_storage_tracing_allowed
Pull networking fixes from Paolo Abeni:
"Smaller than usual with no fixes from any subtree.
Current release - regressions:
- core: fix race of rtnl_net_lock(dev_net(dev))
Previous releases - regressions:
- core: remove the single page frag cache for good
- flow_dissector: fix handling of mixed port and port-range keys
- sched: cls_api: fix error handling causing NULL dereference
- tcp:
- adjust rcvq_space after updating scaling ratio
- drop secpath at the same time as we currently drop dst
- eth: gtp: suppress list corruption splat in gtp_net_exit_batch_rtnl().
Previous releases - always broken:
- vsock:
- fix variables initialization during resuming
- for connectible sockets allow only connected
- eth:
- geneve: fix use-after-free in geneve_find_dev()
- ibmvnic: don't reference skb after sending to VIOS"
* tag 'net-6.14-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (34 commits)
Revert "net: skb: introduce and use a single page frag cache"
net: allow small head cache usage with large MAX_SKB_FRAGS values
nfp: bpf: Add check for nfp_app_ctrl_msg_alloc()
tcp: drop secpath at the same time as we currently drop dst
net: axienet: Set mac_managed_pm
arp: switch to dev_getbyhwaddr() in arp_req_set_public()
net: Add non-RCU dev_getbyhwaddr() helper
sctp: Fix undefined behavior in left shift operation
selftests/bpf: Add a specific dst port matching
flow_dissector: Fix port range key handling in BPF conversion
selftests/net/forwarding: Add a test case for tc-flower of mixed port and port-range
flow_dissector: Fix handling of mixed port and port-range keys
geneve: Suppress list corruption splat in geneve_destroy_tunnels().
gtp: Suppress list corruption splat in gtp_net_exit_batch_rtnl().
dev: Use rtnl_net_dev_lock() in unregister_netdev().
net: Fix dev_net(dev) race in unregister_netdevice_notifier_dev_net().
net: Add net_passive_inc() and net_passive_dec().
net: pse-pd: pd692x0: Fix power limit retrieval
MAINTAINERS: trim the GVE entry
gve: set xdp redirect target only when it is available
...
Verify that for a connectible AF_VSOCK socket, merely having a transport
assigned is insufficient; socket must be connected for the sockmap to
accept.
This does not test datagram vsocks. Even though it hardly matters. VMCI is
the only transport that features VSOCK_TRANSPORT_F_DGRAM, but it has an
unimplemented vsock_transport::readskb() callback, making it unsupported by
BPF/sockmap.
Signed-off-by: Michal Luczaj <mhal@rbox.co>
Acked-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Commit 515745445e ("selftest/bpf: Add test for vsock removal from sockmap
on close()") added test that checked if proto::close() callback was invoked
on AF_VSOCK socket release. I.e. it verified that a close()d vsock does
indeed get removed from the sockmap.
It was done simply by creating a socket pair and attempting to replace a
close()d one with its peer. Since, due to a recent change, sockmap does not
allow updating index with a non-established connectible vsock, redo it with
a freshly established one.
Signed-off-by: Michal Luczaj <mhal@rbox.co>
Acked-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
