Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-11-17 01:22:07 +00:00
Code Issues Packages Projects Releases Wiki Activity
b4150b6881
linux/drivers/target
History
Bodo Stroesser b4150b6881 scsi: target: tcmu: Fix xarray RCU warning 
Commit f5ce815f34 ("scsi: target: tcmu: Support DATA_BLOCK_SIZE = N *
PAGE_SIZE") introduced xas_next() calls to iterate xarray elements.  These
calls triggered the WARNING "suspicious RCU usage" at tcmu device set up
[1]. In the call stack of xas_next(), xas_load() was called.  According to
its comment, this function requires "the xa_lock or the RCU lock".

To avoid the warning:

 - Guard the small loop calling xas_next() in tcmu_get_empty_block with RCU
   lock.

 - In the large loop in tcmu_copy_data using RCU lock would possibly
   disable preemtion for a long time (copy multi MBs). Therefore replace
   XA_STATE, xas_set and xas_next with a single xa_load.

[1]

[ 1899.867091] =============================
[ 1899.871199] WARNING: suspicious RCU usage
[ 1899.875310] 5.13.0-rc1+ #41 Not tainted
[ 1899.879222] -----------------------------
[ 1899.883299] include/linux/xarray.h:1182 suspicious rcu_dereference_check() usage!
[ 1899.890940] other info that might help us debug this:
[ 1899.899082] rcu_scheduler_active = 2, debug_locks = 1
[ 1899.905719] 3 locks held by kworker/0:1/1368:
[ 1899.910161]  #0: ffffa1f8c8b98738 ((wq_completion)target_submission){+.+.}-{0:0}, at: process_one_work+0x1ee/0x580
[ 1899.920732]  #1: ffffbd7040cd7e78 ((work_completion)(&q->sq.work)){+.+.}-{0:0}, at: process_one_work+0x1ee/0x580
[ 1899.931146]  #2: ffffa1f8d1c99768 (&udev->cmdr_lock){+.+.}-{3:3}, at: tcmu_queue_cmd+0xea/0x160 [target_core_user]
[ 1899.941678] stack backtrace:
[ 1899.946093] CPU: 0 PID: 1368 Comm: kworker/0:1 Not tainted 5.13.0-rc1+ #41
[ 1899.953070] Hardware name: System manufacturer System Product Name/PRIME Z270-A, BIOS 1302 03/15/2018
[ 1899.962459] Workqueue: target_submission target_queued_submit_work [target_core_mod]
[ 1899.970337] Call Trace:
[ 1899.972839]  dump_stack+0x6d/0x89
[ 1899.976222]  xas_descend+0x10e/0x120
[ 1899.979875]  xas_load+0x39/0x50
[ 1899.983077]  tcmu_get_empty_blocks+0x115/0x1c0 [target_core_user]
[ 1899.989318]  queue_cmd_ring+0x1da/0x630 [target_core_user]
[ 1899.994897]  ? rcu_read_lock_sched_held+0x3f/0x70
[ 1899.999695]  ? trace_kmalloc+0xa6/0xd0
[ 1900.003501]  ? __kmalloc+0x205/0x380
[ 1900.007167]  tcmu_queue_cmd+0x12f/0x160 [target_core_user]
[ 1900.012746]  __target_execute_cmd+0x23/0xa0 [target_core_mod]
[ 1900.018589]  transport_generic_new_cmd+0x1f3/0x370 [target_core_mod]
[ 1900.025046]  transport_handle_cdb_direct+0x34/0x50 [target_core_mod]
[ 1900.031517]  target_queued_submit_work+0x43/0xe0 [target_core_mod]
[ 1900.037837]  process_one_work+0x268/0x580
[ 1900.041952]  ? process_one_work+0x580/0x580
[ 1900.046195]  worker_thread+0x55/0x3b0
[ 1900.049921]  ? process_one_work+0x580/0x580
[ 1900.054192]  kthread+0x143/0x160
[ 1900.057499]  ? kthread_create_worker_on_cpu+0x40/0x40
[ 1900.062661]  ret_from_fork+0x1f/0x30

Link: https://lore.kernel.org/r/20210519135440.26773-1-bostroesser@gmail.com
Fixes: f5ce815f34 ("scsi: target: tcmu: Support DATA_BLOCK_SIZE = N * PAGE_SIZE")
Reported-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Tested-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Signed-off-by: Bodo Stroesser <bostroesser@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2021-05-21 16:15:48 -04:00
..
iscsi Merge branch '5.12/scsi-fixes' into 5.13/scsi-staging 2021-04-12 21:41:54 -04:00
loopback scsi: target: tcm_loop: Use LIO wq cmd submission helper 2021-03-04 17:37:02 -05:00
sbp scsi: target: sbp_target: Convert to new submission API 2021-03-04 17:37:01 -05:00
tcm_fc scsi: target: tcm_fc: Fix a kernel-doc header 2021-04-15 22:44:41 -04:00
Kconfig treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
Makefile
target_core_alua.c scsi: target: alua: Remove in_interrupt() usage in core_alua_check_nonop_delay() 2021-01-22 20:25:25 -05:00
target_core_alua.h
target_core_configfs.c scsi: target: Shorten ALUA error messages 2021-04-15 22:44:41 -04:00
target_core_device.c scsi: target: Make the virtual LUN 0 device 2021-04-05 23:26:39 -04:00
target_core_fabric_configfs.c scsi: target: core: Make completion affinity configurable 2021-03-04 17:37:03 -05:00
target_core_fabric_lib.c scsi: target: Handle short iSIDs 2020-07-08 00:14:34 -04:00
target_core_file.c scsi: target: core: file: Don't duplicate memset(0xff) 2021-03-09 23:47:18 -05:00
target_core_file.h
target_core_hba.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
target_core_iblock.c scsi: target: iblock: Fix type of logs_per_phys 2021-03-09 23:47:17 -05:00
target_core_iblock.h scsi: target: iblock: Add backend plug/unplug callouts 2021-03-04 17:37:02 -05:00
target_core_internal.h scsi: target: core: Make completion affinity configurable 2021-03-04 17:37:03 -05:00
target_core_pr.c scsi: target: Fix two format specifiers 2021-04-15 22:44:41 -04:00
target_core_pr.h scsi: target/core: Rework the SPC-2 reservation handling code 2019-04-12 20:20:05 -04:00
target_core_pscsi.c SCSI misc on 20210428 2021-04-28 17:22:10 -07:00
target_core_pscsi.h
target_core_rd.c scsi: target: Add the DUMMY flag to rd_mcp 2021-04-05 23:26:38 -04:00
target_core_rd.h scsi: target: Add the DUMMY flag to rd_mcp 2021-04-05 23:26:38 -04:00
target_core_sbc.c scsi: target: core: Get rid of warning in compare_and_write_do_cmp() 2021-03-09 23:47:18 -05:00
target_core_spc.c scsi: target: Make the virtual LUN 0 device 2021-04-05 23:26:39 -04:00
target_core_stat.c scsi: target: core: Remove unused macros NONE and ISPRINT 2021-03-09 23:47:18 -05:00
target_core_tmr.c scsi: target: core: Flush submission work during TMR processing 2021-03-04 17:37:02 -05:00
target_core_tpg.c scsi: target: Drop sess_cmd_lock from I/O path 2020-11-04 22:39:37 -05:00
target_core_transport.c scsi: target: core: Avoid smp_processor_id() in preemptible code 2021-05-21 16:14:02 -04:00
target_core_ua.c scsi: target: use an enum to track emulate_ua_intlck_ctrl 2020-02-21 17:37:16 -05:00
target_core_ua.h
target_core_user.c scsi: target: tcmu: Fix xarray RCU warning 2021-05-21 16:15:48 -04:00
target_core_xcopy.c scsi: target: core: Add gfp_t arg to target_cmd_init_cdb() 2021-03-04 17:37:02 -05:00
target_core_xcopy.h scsi: target: Fix XCOPY NAA identifier lookup 2021-01-11 17:06:48 -05:00