dm crypt: defer decryption to a tasklet if interrupts disabled
On some specific hardware on early boot we occasionally get:
[ 1193.920255][ T0] BUG: sleeping function called from invalid context at mm/mempool.c:381
[ 1193.936616][ T0] in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 0, name: swapper/69
[ 1193.953233][ T0] no locks held by swapper/69/0.
[ 1193.965871][ T0] irq event stamp: 575062
[ 1193.977724][ T0] hardirqs last enabled at (575061): [<ffffffffab73f662>] tick_nohz_idle_exit+0xe2/0x3e0
[ 1194.002762][ T0] hardirqs last disabled at (575062): [<ffffffffab74e8af>] flush_smp_call_function_from_idle+0x4f/0x80
[ 1194.029035][ T0] softirqs last enabled at (575050): [<ffffffffad600fd2>] asm_call_irq_on_stack+0x12/0x20
[ 1194.054227][ T0] softirqs last disabled at (575043): [<ffffffffad600fd2>] asm_call_irq_on_stack+0x12/0x20
[ 1194.079389][ T0] CPU: 69 PID: 0 Comm: swapper/69 Not tainted 5.10.6-cloudflare-kasan-2021.1.4-dev #1
[ 1194.104103][ T0] Hardware name: NULL R162-Z12-CD/MZ12-HD4-CD, BIOS R10 06/04/2020
[ 1194.119591][ T0] Call Trace:
[ 1194.130233][ T0] dump_stack+0x9a/0xcc
[ 1194.141617][ T0] ___might_sleep.cold+0x180/0x1b0
[ 1194.153825][ T0] mempool_alloc+0x16b/0x300
[ 1194.165313][ T0] ? remove_element+0x160/0x160
[ 1194.176961][ T0] ? blk_mq_end_request+0x4b/0x490
[ 1194.188778][ T0] crypt_convert+0x27f6/0x45f0 [dm_crypt]
[ 1194.201024][ T0] ? rcu_read_lock_sched_held+0x3f/0x70
[ 1194.212906][ T0] ? module_assert_mutex_or_preempt+0x3e/0x70
[ 1194.225318][ T0] ? __module_address.part.0+0x1b/0x3a0
[ 1194.237212][ T0] ? is_kernel_percpu_address+0x5b/0x190
[ 1194.249238][ T0] ? crypt_iv_tcw_ctr+0x4a0/0x4a0 [dm_crypt]
[ 1194.261593][ T0] ? is_module_address+0x25/0x40
[ 1194.272905][ T0] ? static_obj+0x8a/0xc0
[ 1194.283582][ T0] ? lockdep_init_map_waits+0x26a/0x700
[ 1194.295570][ T0] ? __raw_spin_lock_init+0x39/0x110
[ 1194.307330][ T0] kcryptd_crypt_read_convert+0x31c/0x560 [dm_crypt]
[ 1194.320496][ T0] ? kcryptd_queue_crypt+0x1be/0x380 [dm_crypt]
[ 1194.333203][ T0] blk_update_request+0x6d7/0x1500
[ 1194.344841][ T0] ? blk_mq_trigger_softirq+0x190/0x190
[ 1194.356831][ T0] blk_mq_end_request+0x4b/0x490
[ 1194.367994][ T0] ? blk_mq_trigger_softirq+0x190/0x190
[ 1194.379693][ T0] flush_smp_call_function_queue+0x24b/0x560
[ 1194.391847][ T0] flush_smp_call_function_from_idle+0x59/0x80
[ 1194.403969][ T0] do_idle+0x287/0x450
[ 1194.413891][ T0] ? arch_cpu_idle_exit+0x40/0x40
[ 1194.424716][ T0] ? lockdep_hardirqs_on_prepare+0x286/0x3f0
[ 1194.436399][ T0] ? _raw_spin_unlock_irqrestore+0x39/0x40
[ 1194.447759][ T0] cpu_startup_entry+0x19/0x20
[ 1194.458038][ T0] secondary_startup_64_no_verify+0xb0/0xbb
IO completion can be queued to a different CPU by the block subsystem as a "call
single function/data". The CPU may run these routines from the idle task, but it
does so with interrupts disabled.
It is not a good idea to do decryption with irqs disabled even in an idle task
context, so just defer it to a tasklet (as is done with requests from hard irqs).
Fixes: 39d42fa96ba1 ("dm crypt: add flags to optionally bypass kcryptd workqueues")
Cc: stable@vger.kernel.org # v5.9+
Signed-off-by: Ignat Korchagin <ignat@cloudflare.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
1 file changed
