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Shin'ichiro Kawasaki 70ca3c57ff scsi: target: core: Avoid smp_processor_id() in preemptible code The BUG message "BUG: using smp_processor_id() in preemptible [00000000] code" was observed for TCMU devices with kernel config DEBUG_PREEMPT. The message was observed when blktests block/005 was run on TCMU devices with fileio backend or user:zbc backend [1]. The commit `1130b499b4` ("scsi: target: tcm_loop: Use LIO wq cmd submission helper") triggered the symptom. The commit modified work queue to handle commands and changed 'current->nr_cpu_allowed' at smp_processor_id() call. The message was also observed at system shutdown when TCMU devices were not cleaned up [2]. The function smp_processor_id() was called in SCSI host work queue for abort handling, and triggered the BUG message. This symptom was observed regardless of the commit `1130b499b4` ("scsi: target: tcm_loop: Use LIO wq cmd submission helper"). To avoid the preemptible code check at smp_processor_id(), get CPU ID with raw_smp_processor_id() instead. The CPU ID is used for performance improvement then thread move to other CPU will not affect the code. [1] [ 56.468103] run blktests block/005 at 2021-05-12 14:16:38 [ 57.369473] check_preemption_disabled: 85 callbacks suppressed [ 57.369480] BUG: using smp_processor_id() in preemptible [00000000] code: fio/1511 [ 57.369506] BUG: using smp_processor_id() in preemptible [00000000] code: fio/1510 [ 57.369512] BUG: using smp_processor_id() in preemptible [00000000] code: fio/1506 [ 57.369552] caller is __target_init_cmd+0x157/0x170 [target_core_mod] [ 57.369606] CPU: 4 PID: 1506 Comm: fio Not tainted 5.13.0-rc1+ #34 [ 57.369613] Hardware name: System manufacturer System Product Name/PRIME Z270-A, BIOS 1302 03/15/2018 [ 57.369617] Call Trace: [ 57.369621] BUG: using smp_processor_id() in preemptible [00000000] code: fio/1507 [ 57.369628] dump_stack+0x6d/0x89 [ 57.369642] check_preemption_disabled+0xc8/0xd0 [ 57.369628] caller is __target_init_cmd+0x157/0x170 [target_core_mod] [ 57.369655] __target_init_cmd+0x157/0x170 [target_core_mod] [ 57.369695] target_init_cmd+0x76/0x90 [target_core_mod] [ 57.369732] tcm_loop_queuecommand+0x109/0x210 [tcm_loop] [ 57.369744] scsi_queue_rq+0x38e/0xc40 [ 57.369761] __blk_mq_try_issue_directly+0x109/0x1c0 [ 57.369779] blk_mq_try_issue_directly+0x43/0x90 [ 57.369790] blk_mq_submit_bio+0x4e5/0x5d0 [ 57.369812] submit_bio_noacct+0x46e/0x4e0 [ 57.369830] __blkdev_direct_IO_simple+0x1a3/0x2d0 [ 57.369859] ? set_init_blocksize.isra.0+0x60/0x60 [ 57.369880] generic_file_read_iter+0x89/0x160 [ 57.369898] blkdev_read_iter+0x44/0x60 [ 57.369906] new_sync_read+0x102/0x170 [ 57.369929] vfs_read+0xd4/0x160 [ 57.369941] __x64_sys_pread64+0x6e/0xa0 [ 57.369946] ? lockdep_hardirqs_on+0x79/0x100 [ 57.369958] do_syscall_64+0x3a/0x70 [ 57.369965] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 57.369973] RIP: 0033:0x7f7ed4c1399f [ 57.369979] Code: 08 89 3c 24 48 89 4c 24 18 e8 7d f3 ff ff 4c 8b 54 24 18 48 8b 54 24 10 41 89 c0 48 8b 74 24 08 8b 3c 24 b8 11 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 04 24 e8 cd f3 ff ff 48 8b [ 57.369983] RSP: 002b:00007ffd7918c580 EFLAGS: 00000293 ORIG_RAX: 0000000000000011 [ 57.369990] RAX: ffffffffffffffda RBX: 00000000015b4540 RCX: 00007f7ed4c1399f [ 57.369993] RDX: 0000000000001000 RSI: 00000000015de000 RDI: 0000000000000009 [ 57.369996] RBP: 00000000015b4540 R08: 0000000000000000 R09: 0000000000000001 [ 57.369999] R10: 0000000000e5c000 R11: 0000000000000293 R12: 00007f7eb5269a70 [ 57.370002] R13: 0000000000000000 R14: 0000000000001000 R15: 00000000015b4568 [ 57.370031] CPU: 7 PID: 1507 Comm: fio Not tainted 5.13.0-rc1+ #34 [ 57.370036] Hardware name: System manufacturer System Product Name/PRIME Z270-A, BIOS 1302 03/15/2018 [ 57.370039] Call Trace: [ 57.370045] dump_stack+0x6d/0x89 [ 57.370056] check_preemption_disabled+0xc8/0xd0 [ 57.370068] __target_init_cmd+0x157/0x170 [target_core_mod] [ 57.370121] target_init_cmd+0x76/0x90 [target_core_mod] [ 57.370178] tcm_loop_queuecommand+0x109/0x210 [tcm_loop] [ 57.370197] scsi_queue_rq+0x38e/0xc40 [ 57.370224] __blk_mq_try_issue_directly+0x109/0x1c0 ... [2] [ 117.458597] BUG: using smp_processor_id() in preemptible [00000000] code: kworker/u16:8 [ 117.467279] caller is __target_init_cmd+0x157/0x170 [target_core_mod] [ 117.473893] CPU: 1 PID: 418 Comm: kworker/u16:6 Not tainted 5.13.0-rc1+ #34 [ 117.481150] Hardware name: System manufacturer System Product Name/PRIME Z270-A, BIOS 8 [ 117.481153] Workqueue: scsi_tmf_7 scmd_eh_abort_handler [ 117.481156] Call Trace: [ 117.481158] dump_stack+0x6d/0x89 [ 117.481162] check_preemption_disabled+0xc8/0xd0 [ 117.512575] target_submit_tmr+0x41/0x150 [target_core_mod] [ 117.519705] tcm_loop_issue_tmr+0xa7/0x100 [tcm_loop] [ 117.524913] tcm_loop_abort_task+0x43/0x60 [tcm_loop] [ 117.530137] scmd_eh_abort_handler+0x7b/0x230 [ 117.534681] process_one_work+0x268/0x580 [ 117.538862] worker_thread+0x55/0x3b0 [ 117.542652] ? process_one_work+0x580/0x580 [ 117.548351] kthread+0x143/0x160 [ 117.551675] ? kthread_create_worker_on_cpu+0x40/0x40 [ 117.556873] ret_from_fork+0x1f/0x30 Link: https://lore.kernel.org/r/20210515070315.215801-1-shinichiro.kawasaki@wdc.com Fixes: `1526d9f10c` ("scsi: target: Make state_list per CPU") Cc: stable@vger.kernel.org # v5.11+ Reviewed-by: Mike Christie <michael.christie@oracle.com> Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>		2021-05-21 16:14:02 -04:00
arch	Handle power-gating of AMD IOMMU perf counters properly when they are used.	2021-05-09 13:00:26 -07:00
block	block-5.13-2021-05-09	2021-05-09 13:25:14 -07:00
certs	Kbuild updates for v5.13 (2nd)	2021-05-08 10:00:11 -07:00
crypto	for-5.13/drivers-2021-04-27	2021-04-28 14:39:37 -07:00
Documentation	A set of scheduler updates:	2021-05-09 13:14:34 -07:00
drivers	scsi: target: core: Avoid smp_processor_id() in preemptible code	2021-05-21 16:14:02 -04:00
fs	3 small SMB3 chmultichannel related changesets (also for stable)	2021-05-09 13:19:29 -07:00
include	block-5.13-2021-05-09	2021-05-09 13:25:14 -07:00
init	Merge branch 'akpm' (patches from Andrew)	2021-05-07 00:34:51 -07:00
ipc	ipc/sem.c: spelling fix	2021-05-07 00:26:34 -07:00
kernel	A set of scheduler updates:	2021-05-09 13:14:34 -07:00
lib	Kbuild updates for v5.13 (2nd)	2021-05-08 10:00:11 -07:00
LICENSES	LICENSES: Add the CC-BY-4.0 license	2020-12-08 10:33:27 -07:00
mm	mm: fix typos in comments	2021-05-07 00:26:35 -07:00
net	Networking fixes for 5.13-rc1, including fixes from bpf, can	2021-05-08 08:31:46 -07:00
samples	Kbuild updates for v5.13 (2nd)	2021-05-08 10:00:11 -07:00
scripts	Kbuild updates for v5.13 (2nd)	2021-05-08 10:00:11 -07:00
security	Simple code cleanup	2021-05-05 12:08:06 -07:00
sound	sound fixes for 5.13-rc1	2021-05-07 11:40:18 -07:00
tools	Kbuild updates for v5.13 (2nd)	2021-05-08 10:00:11 -07:00
usr	.gitignore: prefix local generated files with a slash	2021-05-02 00:43:35 +09:00
virt	KVM: Boost vCPU candidate in user mode which is delivering interrupt	2021-04-21 12:20:03 -04:00
.clang-format	cxl for 5.12	2021-02-24 09:38:36 -08:00
.cocciconfig
.get_maintainer.ignore	Opt out of scripts/get_maintainer.pl	2019-05-16 10:53:40 -07:00
.gitattributes	.gitattributes: use 'dts' diff driver for dts files	2019-12-04 19:44:11 -08:00
.gitignore	.gitignore: ignore only top-level modules.builtin	2021-05-02 00:43:35 +09:00
.mailmap	It's been a relatively busy cycle in docsland, though more than usually	2021-04-26 13:22:43 -07:00
COPYING	COPYING: state that all contributions really are covered by this file	2020-02-10 13:32:20 -08:00
CREDITS	MAINTAINERS: move Murali Karicheri to credits	2021-04-29 15:47:30 -07:00
Kbuild	kbuild: rename hostprogs-y/always to hostprogs/always-y	2020-02-04 01:53:07 +09:00
Kconfig	kbuild: ensure full rebuild when the compiler is updated	2020-05-12 13:28:33 +09:00
MAINTAINERS	Networking fixes for 5.13-rc1, including fixes from bpf, can	2021-05-08 08:31:46 -07:00
Makefile	Linux 5.13-rc1	2021-05-09 14:17:44 -07:00
README	Drop all 00-INDEX files from Documentation/	2018-09-09 15:08:58 -06:00

README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.