On 1/16/23 06:59, Steffen Maier wrote:
Hi all,
since a few days/weeks, we sometimes see below alua and sleep related
kernel BUG and WARNING (with panic_on_warn) in our CI.
It reminds me of
[PATCH 0/2] Rework how the ALUA driver calls scsi_device_put()
https://lore.kernel.org/linux-scsi/166986602290.2101055.17397734326843853911.b4-ty@xxxxxxxxxx/
which I thought was the fix and went into 6.2-rc(1?) on 2022-12-14 with
[GIT PULL] first round of SCSI updates for the 6.1+ merge window
https://lore.kernel.org/linux-scsi/b2e824bbd1e40da64d2d01657f2f7a67b98919fb.camel@xxxxxxxxxxxxxxxxxxxxx/T/#u
Due to limited history, I cannot tell exactly when problems started and
whether it really correlates to above.
Test workload are all kinds of coverage tests for zfcp recovery
including scsi device removal and/or rescan.
[ 4569.045992] BUG: sleeping function called from invalid context at
drivers/scsi/device_handler/scsi_dh_alua.c:992
[ 4569.046003] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 0,
name: swapper/8
[ 4569.046013] preempt_count: 101, expected: 0
[ 4569.046023] RCU nest depth: 0, expected: 0
[ 4569.046033] no locks held by swapper/8/0.
[ 4569.046042] Preemption disabled at:
[ 4569.046046] [<000000017e27ce4e>] __slab_alloc.constprop.0+0x36/0xb8
[ 4569.046072] CPU: 8 PID: 0 Comm: swapper/8 Tainted: G W
6.2.0-20230114.rc3.git0.46e26dd43df0.300.fc37.s390x+debug #1
[ 4569.046084] Hardware name: IBM 2964 NC9 702 (z/VM 6.4.0)
[ 4569.046094] Call Trace:
[ 4569.046102] [<000000017ed21bcc>] dump_stack_lvl+0xac/0x100
[ 4569.046118] [<000000017df9192c>] __might_resched+0x284/0x2c8
[ 4569.046131] [<000003ff7fb9c874>] alua_rtpg_queue+0x3c/0x98
[scsi_dh_alua]
[ 4569.046146] [<000003ff7fb9cfb2>] alua_check+0x122/0x250 [scsi_dh_alua]
[ 4569.046167] [<000003ff7fb9d562>] alua_check_sense+0x172/0x228
[scsi_dh_alua]
[ 4569.046179] [<000000017e96b3e2>] scsi_check_sense+0x8a/0x2e0
[ 4569.046191] [<000000017e96e4b6>] scsi_decide_disposition+0x286/0x298
[ 4569.046201] [<000000017e972bca>] scsi_complete+0x6a/0x108
[ 4569.046212] [<000000017e746906>] blk_complete_reqs+0x6e/0x88
[ 4569.046227] [<000000017ed3830e>] __do_softirq+0x13e/0x6b8
[ 4569.046238] [<000000017df57902>] __irq_exit_rcu+0x14a/0x170
[ 4569.046264] [<000000017df58472>] irq_exit_rcu+0x22/0x50
[ 4569.046275] [<000000017ed2242a>] do_ext_irq+0x10a/0x1d0
[ 4569.046286] [<000000017ed36156>] ext_int_handler+0xd6/0x110
[ 4569.046296] [<000000017ed362e6>] psw_idle_exit+0x0/0xa
[ 4569.046307] ([<000000017defc5da>] arch_cpu_idle+0x52/0xe0)
[ 4569.046318] [<000000017ed34744>] default_idle_call+0x84/0xd0
[ 4569.046329] [<000000017dfbe4cc>] do_idle+0xfc/0x1b8
[ 4569.046340] [<000000017dfbe80e>] cpu_startup_entry+0x36/0x40
[ 4569.046350] [<000000017df11964>] smp_start_secondary+0x14c/0x160
[ 4569.046371] [<000000017ed3658e>] restart_int_handler+0x6e/0x90
[ 4569.046381] no locks held by swapper/8/0.
Hi Steffen,
Thanks for your report and also for having included this call trace. Is
my understanding correct that alua_rtpg_queue+0x3c refers to the
might_sleep() near the start of alua_rtpg_queue()? If so, please help
with testing the following patch:
diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c
b/drivers/scsi/device_handler/scsi_dh_alua.c
index 49cc18a87473..79afa7acdfbc 100644
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -989,8 +989,6 @@ static bool alua_rtpg_queue(struct alua_port_group
int start_queue = 0;
unsigned long flags;
- might_sleep();
-
if (WARN_ON_ONCE(!pg) || scsi_device_get(sdev))
return false;
I'm proposing this change because the context from which a request is
queued should hold a reference on 'sdev' while a request is in progress
so alua_check_sense() should not trigger the scsi_device_put() call in
alua_rtpg_queue().
Thanks,
Bart.
