[moderation] [scsi?] KCSAN: data-race in sg_fill_request_table / sg_rq_end_io (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 254f49634ee1 Linux 7.1-rc1
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=169f09ba580000
kernel config: https://syzkaller.appspot.com/x/.config?x=2e40c0f41e01837e
dashboard link: https://syzkaller.appspot.com/bug?extid=82c7fc080122cd8d1f25
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
CC: [James.B...@HansenPartnership.com dgil...@interlog.com linux-...@vger.kernel.org linux...@vger.kernel.org martin....@oracle.com]

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/cc8abe4cd3cd/disk-254f4963.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/09a4207e49b7/vmlinux-254f4963.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e3e4f7ccecb9/bzImage-254f4963.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+82c7fc...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in sg_fill_request_table / sg_rq_end_io

write to 0xffff88812022c109 of 1 bytes by interrupt on cpu 1:
sg_rq_end_io+0x158/0x770 drivers/scsi/sg.c:1348
__blk_mq_end_request+0x2f4/0x370 block/blk-mq.c:1168
scsi_end_request+0x29c/0x4c0 drivers/scsi/scsi_lib.c:681
scsi_io_completion+0x194/0x1d0 drivers/scsi/scsi_lib.c:1095
scsi_finish_command+0x1c7/0x1e0 drivers/scsi/scsi.c:198
scsi_complete+0x155/0x4f0 drivers/scsi/scsi_lib.c:1569
blk_complete_reqs block/blk-mq.c:1253 [inline]
blk_done_softirq+0x77/0xb0 block/blk-mq.c:1258
handle_softirqs+0xb9/0x280 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0x42/0xd0 kernel/softirq.c:735
common_interrupt+0x83/0x90 arch/x86/kernel/irq.c:326
asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:688
syscall_enter_from_user_mode_work include/linux/entry-common.h:144 [inline]
syscall_enter_from_user_mode include/linux/entry-common.h:178 [inline]
do_syscall_64+0x82/0x3b0 arch/x86/entry/syscall_64.c:89
entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88812022c109 of 1 bytes by task 24144 on cpu 0:
sg_fill_request_table+0x5f/0x1d0 drivers/scsi/sg.c:867
sg_ioctl_common drivers/scsi/sg.c:1084 [inline]
sg_ioctl+0x6a6/0x1340 drivers/scsi/sg.c:1158
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+0x1563/0x3020 arch/x86/include/generated/asm/syscalls_64.h:17
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x12c/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00 -> 0x01

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 24144 Comm: syz.3.9360 Tainted: G W syzkaller #0 PREEMPT(full)
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
==================================================================


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