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Marek and Guenter reported that commit287905e68d("driver core: Expose device link details in sysfs") caused sleeping/scheduling while atomic warnings. BUG: sleeping function called from invalid context at kernel/locking/mutex.c:935 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 12, name: kworker/0:1 2 locks held by kworker/0:1/12: #0: ee8074a8 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x174/0x7dc #1: ee921f20 ((work_completion)(&sdp->work)){+.+.}-{0:0}, at: process_one_work+0x174/0x7dc Preemption disabled at: [<c01b10f0>] srcu_invoke_callbacks+0xc0/0x154 ----- 8< ----- SNIP [<c064590c>] (device_del) from [<c0645c9c>] (device_unregister+0x24/0x64) [<c0645c9c>] (device_unregister) from [<c01b10fc>] (srcu_invoke_callbacks+0xcc/0x154) [<c01b10fc>] (srcu_invoke_callbacks) from [<c01493c4>] (process_one_work+0x234/0x7dc) [<c01493c4>] (process_one_work) from [<c01499b0>] (worker_thread+0x44/0x51c) [<c01499b0>] (worker_thread) from [<c0150bf4>] (kthread+0x158/0x1a0) [<c0150bf4>] (kthread) from [<c0100114>] (ret_from_fork+0x14/0x20) Exception stack(0xee921fb0 to 0xee921ff8) This was caused by the device link device being released in the context of srcu_invoke_callbacks(). There is no need to wait till the RCU callback to release the device link device. So release the device earlier and move the call_srcu() into the device release code. That way, the memory will get freed only after the device is released AND the RCU callback is called. Fixes:287905e68d("driver core: Expose device link details in sysfs") Reported-by: Marek Szyprowski <m.szyprowski@samsung.com> Reported-by: Guenter Roeck <linux@roeck-us.net> Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org> Signed-off-by: Saravana Kannan <saravanak@google.com> Tested-by: Marek Szyprowski <m.szyprowski@samsung.com> Tested-by: Guenter Roeck <linux@roeck-us.net> Link: https://lore.kernel.org/r/20200716214523.2924704-1-saravanak@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
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