io_uring-5.8-2020-06-26
io_uring: fix current->mm NULL dereference on exit
Don't reissue requests from io_iopoll_reap_events(), the task may not
have mm, which ends up with NULL. It's better to kill everything off on
exit anyway.
[ 677.734670] RIP: 0010:io_iopoll_complete+0x27e/0x630
...
[ 677.734679] Call Trace:
[ 677.734695] ? __send_signal+0x1f2/0x420
[ 677.734698] ? _raw_spin_unlock_irqrestore+0x24/0x40
[ 677.734699] ? send_signal+0xf5/0x140
[ 677.734700] io_iopoll_getevents+0x12f/0x1a0
[ 677.734702] io_iopoll_reap_events.part.0+0x5e/0xa0
[ 677.734703] io_ring_ctx_wait_and_kill+0x132/0x1c0
[ 677.734704] io_uring_release+0x20/0x30
[ 677.734706] __fput+0xcd/0x230
[ 677.734707] ____fput+0xe/0x10
[ 677.734709] task_work_run+0x67/0xa0
[ 677.734710] do_exit+0x35d/0xb70
[ 677.734712] do_group_exit+0x43/0xa0
[ 677.734713] get_signal+0x140/0x900
[ 677.734715] do_signal+0x37/0x780
[ 677.734717] ? enqueue_hrtimer+0x41/0xb0
[ 677.734718] ? recalibrate_cpu_khz+0x10/0x10
[ 677.734720] ? ktime_get+0x3e/0xa0
[ 677.734721] ? lapic_next_deadline+0x26/0x30
[ 677.734723] ? tick_program_event+0x4d/0x90
[ 677.734724] ? __hrtimer_get_next_event+0x4d/0x80
[ 677.734726] __prepare_exit_to_usermode+0x126/0x1c0
[ 677.734741] prepare_exit_to_usermode+0x9/0x40
[ 677.734742] idtentry_exit_cond_rcu+0x4c/0x60
[ 677.734743] sysvec_reschedule_ipi+0x92/0x160
[ 677.734744] ? asm_sysvec_reschedule_ipi+0xa/0x20
[ 677.734745] asm_sysvec_reschedule_ipi+0x12/0x20
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
1 file changed
