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KCSAN: data-race in sg_common_write / sg_finish_rem_req (6)

Status: moderation: reported on 2025/10/30 14:38
Subsystems: scsi
[Documentation on labels]
Reported-by: syzbot+3fd8cb6e827442a26422@syzkaller.appspotmail.com
First crash: 54d, last: 8h44m
Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in sg_common_write / sg_finish_rem_req (4) scsi 6 6 305d 328d 0/29 auto-obsoleted due to no activity on 2025/04/18 04:19
upstream KCSAN: data-race in sg_common_write / sg_finish_rem_req scsi 6 3 794d 827d 0/29 auto-obsoleted due to no activity on 2023/11/25 03:57
upstream KCSAN: data-race in sg_common_write / sg_finish_rem_req (2) scsi 6 1 549d 549d 0/29 auto-obsoleted due to no activity on 2024/07/27 17:57
upstream KCSAN: data-race in sg_common_write / sg_finish_rem_req (5) scsi 6 7 149d 240d 0/29 auto-obsoleted due to no activity on 2025/09/21 21:52
upstream KCSAN: data-race in sg_common_write / sg_finish_rem_req (3) scsi 6 14 433d 499d 0/29 auto-obsoleted due to no activity on 2024/11/20 21:45

Sample crash report:
==================================================================
BUG: KCSAN: data-race in sg_common_write / sg_finish_rem_req

write to 0xffff88811a71931d of 1 bytes by task 3423 on cpu 1:
 sg_unlink_reserve drivers/scsi/sg.c:2059 [inline]
 sg_finish_rem_req+0x11f/0x270 drivers/scsi/sg.c:1841
 sg_rq_end_io_usercontext+0x38/0x1c0 drivers/scsi/sg.c:1301
 process_one_work kernel/workqueue.c:3257 [inline]
 process_scheduled_works+0x4ce/0x9d0 kernel/workqueue.c:3340
 worker_thread+0x582/0x770 kernel/workqueue.c:3421
 kthread+0x489/0x510 kernel/kthread.c:463
 ret_from_fork+0x149/0x290 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

read to 0xffff88811a71931d of 1 bytes by task 22907 on cpu 0:
 sg_start_req drivers/scsi/sg.c:1781 [inline]
 sg_common_write+0x961/0xc30 drivers/scsi/sg.c:799
 sg_new_write+0x7b6/0x890 drivers/scsi/sg.c:766
 sg_ioctl_common drivers/scsi/sg.c:931 [inline]
 sg_ioctl+0xb81/0x1360 drivers/scsi/sg.c:1156
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xce/0x140 fs/ioctl.c:583
 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:583
 x64_sys_call+0x14b0/0x3000 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xca/0x2b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x01 -> 0x00

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 22907 Comm: syz.8.7266 Tainted: G        W           syzkaller #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
==================================================================

Crashes (7):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/12/23 16:51 upstream b927546677c8 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in sg_common_write / sg_finish_rem_req
2025/12/05 23:22 upstream d1d36025a617 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in sg_common_write / sg_finish_rem_req
2025/11/25 05:18 upstream ac3fd01e4c1e 64219f15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in sg_common_write / sg_finish_rem_req
2025/11/22 14:32 upstream 2eba5e05d9bc 4fb8ef37 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in sg_common_write / sg_finish_rem_req
2025/11/20 14:07 upstream 23cb64fb7625 2cc4c24a .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in sg_common_write / sg_finish_rem_req
2025/11/01 19:45 upstream 691d401c7e0e 2c50b6a9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in sg_common_write / sg_finish_rem_req
2025/10/30 14:38 upstream e53642b87a4f fd2207e7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in sg_common_write / sg_finish_rem_req
* Struck through repros no longer work on HEAD.