Files
linux/lib
Kefeng Wang 245f092268 mm: hwpoison: coredump: support recovery from dump_user_range()
dump_user_range() is used to copy the user page to a coredump file, but if
a hardware memory error occurred during copy, which called from
__kernel_write_iter() in dump_user_range(), it crashes,

  CPU: 112 PID: 7014 Comm: mca-recover Not tainted 6.3.0-rc2 #425

  pc : __memcpy+0x110/0x260
  lr : _copy_from_iter+0x3bc/0x4c8
  ...
  Call trace:
   __memcpy+0x110/0x260
   copy_page_from_iter+0xcc/0x130
   pipe_write+0x164/0x6d8
   __kernel_write_iter+0x9c/0x210
   dump_user_range+0xc8/0x1d8
   elf_core_dump+0x308/0x368
   do_coredump+0x2e8/0xa40
   get_signal+0x59c/0x788
   do_signal+0x118/0x1f8
   do_notify_resume+0xf0/0x280
   el0_da+0x130/0x138
   el0t_64_sync_handler+0x68/0xc0
   el0t_64_sync+0x188/0x190

Generally, the '->write_iter' of file ops will use copy_page_from_iter()
and copy_page_from_iter_atomic(), change memcpy() to copy_mc_to_kernel()
in both of them to handle #MC during source read, which stop coredump
processing and kill the task instead of kernel panic, but the source
address may not always a user address, so introduce a new copy_mc flag in
struct iov_iter{} to indicate that the iter could do a safe memory copy,
also introduce the helpers to set/cleck the flag, for now, it's only used
in coredump's dump_user_range(), but it could expand to any other
scenarios to fix the similar issue.

Link: https://lkml.kernel.org/r/20230417045323.11054-1-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Tong Tiangen <tongtiangen@huawei.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-05-02 17:21:50 -07:00
..
2022-05-09 17:20:37 -07:00
2023-03-06 15:54:54 -08:00
2021-05-06 19:24:12 -07:00
2022-09-26 12:19:12 -07:00
2023-04-08 13:45:37 -07:00
2021-01-21 14:06:00 -07:00
2022-03-07 12:48:35 -07:00
2021-08-19 09:02:55 +09:00
2022-09-01 18:04:43 +02:00
2023-02-02 22:50:01 -08:00
2023-02-02 22:50:01 -08:00
2023-02-02 22:50:01 -08:00
2022-04-22 21:30:57 +02:00
2023-02-15 15:44:43 +01:00
2021-01-03 20:05:18 -05:00
2023-03-19 10:02:04 -07:00
2022-03-07 12:48:35 -07:00
2022-04-29 14:38:01 -07:00
2022-07-10 13:55:49 -07:00
2022-10-03 14:03:21 -07:00
2021-08-19 09:02:55 +09:00
2021-07-08 11:48:20 -07:00
2023-04-17 18:01:23 +02:00
2021-07-08 11:48:20 -07:00
2018-10-16 13:45:44 +02:00
2022-10-03 17:34:32 -07:00
2021-07-08 11:48:20 -07:00
2021-07-08 11:48:20 -07:00
2023-01-27 11:42:57 -08:00
2021-06-18 11:43:09 +02:00
2021-07-08 11:48:20 -07:00
2022-11-11 18:18:05 -08:00
2022-01-20 08:52:54 +02:00
2018-10-15 16:31:29 -04:00