On 1/18/23 17:17, Steffen Maier wrote:
On 1/18/23 01:29, Bart Van Assche wrote:
On 1/17/23 14:03, Martin Wilck wrote:
On Tue, 2023-01-17 at 13:52 -0800, Bart Van Assche wrote:
On 1/17/23 13:48, Martin Wilck wrote:
Yes, that was my suggestion. Just defer the scsi_device_put() call
in
alua_rtpg_queue() in the case where the actual RTPG handler is not
queued. I won't have time for that before next week though.
[PATCH] scsi: device_handler: alua: Remove a might_sleep() annotation
The might_sleep() annotation in alua_rtpg_queue() is not correct since the
command completion code may call this function from atomic context.
Calling alua_rtpg_queue() from atomic context in the command completion
path is fine since request submitters must hold an sdev reference until
command execution has completed. This patch fixes the following kernel
warning:
BUG: sleeping function called from invalid context at
drivers/scsi/device_handler/scsi_dh_alua.c:992
Call Trace:
dump_stack_lvl+0xac/0x100
__might_resched+0x284/0x2c8
alua_rtpg_queue+0x3c/0x98 [scsi_dh_alua]
alua_check+0x122/0x250 [scsi_dh_alua]
alua_check_sense+0x172/0x228 [scsi_dh_alua]
scsi_check_sense+0x8a/0x2e0
scsi_decide_disposition+0x286/0x298
scsi_complete+0x6a/0x108
blk_complete_reqs+0x6e/0x88
__do_softirq+0x13e/0x6b8
__irq_exit_rcu+0x14a/0x170
irq_exit_rcu+0x22/0x50
do_ext_irq+0x10a/0x1d0
Reported-by: Steffen Maier <maier@xxxxxxxxxxxxx>
Cc: Steffen Maier <maier@xxxxxxxxxxxxx>
Cc: Martin Wilck <mwilck@xxxxxxxx>
Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
---
drivers/scsi/device_handler/scsi_dh_alua.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c
b/drivers/scsi/device_handler/scsi_dh_alua.c
index 55a5073248f8..362fa631f39b 100644
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -987,6 +987,9 @@ static void alua_rtpg_work(struct work_struct *work)
*
* Returns true if and only if alua_rtpg_work() will be called asynchronously.
* That function is responsible for calling @qdata->fn().
+ *
+ * Context: may be called from atomic context (alua_check()) only if the caller
+ * holds an sdev reference.
*/
static bool alua_rtpg_queue(struct alua_port_group *pg,
struct scsi_device *sdev,
@@ -995,8 +998,6 @@ static bool alua_rtpg_queue(struct alua_port_group *pg,
int start_queue = 0;
unsigned long flags;
- might_sleep();
-
I had removed those two lines yesterday for our CI kernel build.
Tonight's run obviously no longer had any related BUG or WARNING.
I checked all dumps from that run to see if anything stalled and whether it was
related to ALUA, but I think we're good.
Tested-by: Steffen Maier <maier@xxxxxxxxxxxxx>
I'm afraid, that might have been too early.
Today, I got BUG/WARNING with a slightly different stack trace where
alua_rtpg_queue calls scsi_device_put(), which in turn contains a might_sleep
but seems called in atomic context:
[ 2517.231562] sd 13:0:0:1073823768: Power-on or device reset occurred
[ 2517.231582] sd 13:0:0:1073823768: [sdax] tag#2787 Done: ADD_TO_MLQUEUE Result: hostbyte=DID_OK driverbyte=DRIVER_OK cmd_age=0s
[ 2517.231590] sd 13:0:0:1073823768: [sdax] tag#2787 CDB: Test Unit Ready 00 00 00 00 00 00
[ 2517.231598] sd 13:0:0:1073823768: [sdax] tag#2787 Sense Key : Unit Attention [current]
[ 2517.231605] sd 13:0:0:1073823768: [sdax] tag#2787 Add. Sense: Power on, reset, or bus device reset occurred
[ 2517.236104] sd 13:0:0:1074348056: Power-on or device reset occurred
[ 2517.236124] BUG: sleeping function called from invalid context at drivers/scsi/scsi.c:591
[ 2517.236130] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 166768, name: systemd-udevd
[ 2517.236137] preempt_count: 100, expected: 0
[ 2517.236143] RCU nest depth: 0, expected: 0
[ 2517.236148] no locks held by systemd-udevd/166768.
[ 2517.236154] Preemption disabled at:
[ 2517.236157] [<000000019704d22e>] __do_softirq+0x5e/0x6b8
[ 2517.236177] CPU: 2 PID: 166768 Comm: systemd-udevd Tainted: G K 6.2.0-20230123.rc5.git2.9dea08313ff5.300.fc37.s390x+debug #1
[ 2517.236185] Hardware name: IBM 8561 T01 703 (z/VM 7.3.0)
[ 2517.236190] Call Trace:
[ 2517.236195] [<00000001970367cc>] dump_stack_lvl+0xac/0x100
[ 2517.236203] [<00000001962a590c>] __might_resched+0x284/0x2c8
[ 2517.236213] [<0000000196c7b34a>] scsi_device_put+0x42/0x60
[ 2517.236224] [<000003ff7fb9c57e>] alua_rtpg_queue.part.0+0xce/0x348 [scsi_dh_alua]
[ 2517.236234] [<000003ff7fb9d20a>] alua_check+0x132/0x260 [scsi_dh_alua]
[ 2517.236241] [<000003ff7fb9d4aa>] alua_check_sense+0x172/0x228 [scsi_dh_alua]
[ 2517.236248] [<0000000196c7fd0e>] scsi_check_sense+0x86/0x2e0
[ 2517.236256] [<0000000196c82cc6>] scsi_decide_disposition+0x286/0x298
[ 2517.236262] [<0000000196c873da>] scsi_complete+0x6a/0x108
[ 2517.236269] [<0000000196a5aeea>] blk_complete_reqs+0x6a/0x88
[ 2517.236281] [<000000019704d30a>] __do_softirq+0x13a/0x6b8
[ 2517.236287] [<000000019626b802>] __irq_exit_rcu+0x14a/0x170
[ 2517.236297] [<000000019626c372>] irq_exit_rcu+0x22/0x50
[ 2517.236303] [<0000000197036fda>] do_ext_irq+0xba/0x1d0
[ 2517.236309] [<000000019704ad06>] ext_int_handler+0xd6/0x110
[ 2517.236315] [<00000001963accd2>] seccomp_run_filters+0x9a/0x198
[ 2517.236328] [<00000001963ad5bc>] __seccomp_filter+0x4c/0x3b8
[ 2517.236334] [<0000000196335f1a>] syscall_trace_enter.constprop.0+0xda/0x310
[ 2517.236345] [<0000000197036bf0>] __do_syscall+0xf0/0x208
[ 2517.236350] [<000000019704aa52>] system_call+0x82/0xb0
[ 2517.236356] no locks held by systemd-udevd/166768.
The same can also happen outside of process context, where it happened to run
alua_rtpg() before an IRQ happened for :
[ 2517.249685] ------------[ cut here ]------------
[ 2517.249691] do not call blocking ops when !TASK_RUNNING; state=2 set at [<0000000197040cb2>] __wait_for_common+0xa2/0x240
[ 2517.249710] WARNING: CPU: 0 PID: 121221 at kernel/sched/core.c:9959 __might_sleep+0x7c/0x98
[ 2517.249719] Modules linked in: kvm af_iucv algif_hash af_alg nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 ip_set nf_tables nfnetlink dm_service_time sunrpc zfcp scsi_transport_fc s390_trng vfio_ccw mdev vfio_iommu_type1 vfio sch_fq_codel ip6_tables ip_tables x_tables configfs ghash_s390 prng chacha_s390 libchacha aes_s390 des_s390 libdes sha3_512_s390 sha3_256_s390 nvme sha512_s390 sha256_s390 sha1_s390 sha_common nvme_core scsi_dh_rdac scsi_dh_emc scsi_dh_alua pkey zcrypt rng_core dm_multipath autofs4
[ 2517.249869] Unloaded tainted modules: test_klp_state3(K):1 test_klp_state2(K):4 test_klp_state(K):3 test_klp_callbacks_demo2(K):2 test_klp_callbacks_demo(K):12 test_klp_atomic_replace(K):2 test_klp_livepatch(K):6 [last unloaded: test_klp_callbacks_demo(K)]
[ 2517.249907] CPU: 0 PID: 121221 Comm: kworker/0:1 Tainted: G W K 6.2.0-20230123.rc5.git2.9dea08313ff5.300.fc37.s390x+debug #1
[ 2517.249915] Hardware name: IBM 8561 T01 703 (z/VM 7.3.0)
[ 2517.249921] Workqueue: kaluad alua_rtpg_work [scsi_dh_alua]
[ 2517.249931] Krnl PSW : 0704d00180000000 00000001962a59d0 (__might_sleep+0x80/0x98)
[ 2517.249944] R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:1 PM:0 RI:0 EA:3
[ 2517.249953] Krnl GPRS: c0000000ffffbfff 0000000080000101 000000000000006d 00000001974ae114
[ 2517.249960] 0000037ffff339a0 0000037ffff33998 0000000000000000 0000000000000001
[ 2517.249966] 0700037ffff33b50 00000000be69c000 000000000000024f 00000001974cb458
[ 2517.249973] 00000000a4080100 00000000a5344220 00000001962a59cc 0000037ffff33b30
[ 2517.249985] Krnl Code: 00000001962a59c0: c020008c269f larl %r2,000000019742a6fe
00000001962a59c6: c0e5006bbf19 brasl %r14,000000019701d7f8
#00000001962a59cc: af000000 mc 0,0
>00000001962a59d0: a7490000 lghi %r4,0
00000001962a59d4: b904003a lgr %r3,%r10
00000001962a59d8: b904002b lgr %r2,%r11
00000001962a59dc: ebaff0a00004 lmg %r10,%r15,160(%r15)
00000001962a59e2: c0f4fffffe53 brcl 15,00000001962a5688
[ 2517.250023] Call Trace:
[ 2517.250028] [<00000001962a59d0>] __might_sleep+0x80/0x98
[ 2517.250036] ([<00000001962a59cc>] __might_sleep+0x7c/0x98)
[ 2517.250043] [<0000000196c7b34a>] scsi_device_put+0x42/0x60
[ 2517.250050] [<000003ff7fb9c57e>] alua_rtpg_queue.part.0+0xce/0x348 [scsi_dh_alua]
[ 2517.250058] [<000003ff7fb9d20a>] alua_check+0x132/0x260 [scsi_dh_alua]
[ 2517.250066] [<000003ff7fb9d4aa>] alua_check_sense+0x172/0x228 [scsi_dh_alua]
[ 2517.250073] [<0000000196c7fd0e>] scsi_check_sense+0x86/0x2e0
[ 2517.250080] [<0000000196c82cc6>] scsi_decide_disposition+0x286/0x298
[ 2517.250087] [<0000000196c873da>] scsi_complete+0x6a/0x108
[ 2517.250095] [<0000000196a5aeea>] blk_complete_reqs+0x6a/0x88
[ 2517.250102] [<000000019704d30a>] __do_softirq+0x13a/0x6b8
[ 2517.250109] [<000000019626b802>] __irq_exit_rcu+0x14a/0x170
[ 2517.250116] [<000000019626c372>] irq_exit_rcu+0x22/0x50
[ 2517.250123] [<0000000197036fda>] do_ext_irq+0xba/0x1d0
[ 2517.250130] [<000000019704ad06>] ext_int_handler+0xd6/0x110
[ 2517.250136] [<0000000197049ac2>] _raw_spin_unlock_irq+0x42/0x70
[ 2517.250143] ([<0000000197049abe>] _raw_spin_unlock_irq+0x3e/0x70)
[ 2517.250150] [<0000000197040cdc>] __wait_for_common+0xcc/0x240
[ 2517.250157] [<0000000196a5bf8e>] blk_execute_rq+0x126/0x1f8
[ 2517.250165] [<0000000196c84f32>] __scsi_execute+0x112/0x260
[ 2517.250172] [<000003ff7fb9d698>] alua_rtpg+0x138/0xb10 [scsi_dh_alua]
[ 2517.250179] [<000003ff7fb9e32c>] alua_rtpg_work+0x2bc/0x4e0 [scsi_dh_alua]
[ 2517.250186] [<000000019628c244>] process_one_work+0x30c/0x730
[ 2517.250197] [<000000019628c6ca>] worker_thread+0x62/0x420
[ 2517.250205] [<0000000196297b08>] kthread+0x138/0x150
[ 2517.250214] [<000000019620f92c>] __ret_from_fork+0x3c/0x58
[ 2517.250222] [<000000019704aa8a>] ret_from_fork+0xa/0x40
[ 2517.250229] 2 locks held by kworker/0:1/121221:
[ 2517.250235] #0: 000000008ba79148 ((wq_completion)kaluad){+.+.}-{0:0}, at: process_one_work+0x232/0x730
[ 2517.250256] #1: 000003800695fdc8 ((work_completion)(&(&pg->rtpg_work)->work)){+.+.}-{0:0}, at: process_one_work+0x232/0x730
[ 2517.250276] Last Breaking-Event-Address:
[ 2517.250281] [<000000019701d85e>] __warn_printk+0x66/0x70
[ 2517.250291] Kernel panic - not syncing: kernel: panic_on_warn set ...
--
Mit freundlichen Gruessen / Kind regards
Steffen Maier
Linux on IBM Z and LinuxONE
https://www.ibm.com/privacy/us/en/
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