[moderation] [scsi?] KCSAN: data-race in sg_fill_request_table / sg_rq_end_io (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: fd57572253bc Merge tag 'sched_ext-for-6.18-rc3-fixes' of g..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=121fac92580000
kernel config: https://syzkaller.appspot.com/x/.config?x=d2e0bc0ae94545f7
dashboard link: https://syzkaller.appspot.com/bug?extid=46cc212ee1e7a4a4e019
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
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/747324970058/disk-fd575722.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/027e4dd56c41/vmlinux-fd575722.xz
kernel image: https://storage.googleapis.com/syzbot-assets/9232192168d7/bzImage-fd575722.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+46cc21...@syzkaller.appspotmail.com

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

write to 0xffff88810c48a111 of 1 bytes by interrupt on cpu 1:
sg_rq_end_io+0x1a2/0x740 drivers/scsi/sg.c:1348
__blk_mq_end_request+0x27e/0x380 block/blk-mq.c:1150
scsi_end_request+0x29c/0x4c0 drivers/scsi/scsi_lib.c:670
scsi_io_completion+0x7f/0x200 drivers/scsi/scsi_lib.c:1078
scsi_finish_command+0x1c7/0x1e0 drivers/scsi/scsi.c:198
scsi_complete+0xc3/0x1e0 drivers/scsi/scsi_lib.c:1547
blk_complete_reqs block/blk-mq.c:1235 [inline]
blk_done_softirq+0x77/0xb0 block/blk-mq.c:1240
handle_softirqs+0xba/0x290 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0x3a/0xc0 kernel/softirq.c:723
common_interrupt+0x83/0x90 arch/x86/kernel/irq.c:318
asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:688
rol32 include/linux/bitops.h:126 [inline]
jhash2 include/linux/jhash.h:139 [inline]
hash_stack lib/stackdepot.c:563 [inline]
stack_depot_save_flags+0x16d/0xb80 lib/stackdepot.c:664
stack_depot_save+0xe/0x20 lib/stackdepot.c:739
ref_tracker_alloc+0x115/0x2f0 lib/ref_tracker.c:278
__netns_tracker_alloc include/net/net_namespace.h:362 [inline]
sk_alloc+0x329/0x360 net/core/sock.c:2311
__netlink_create net/netlink/af_netlink.c:628 [inline]
__netlink_kernel_create+0xe9/0x560 net/netlink/af_netlink.c:2020
netlink_kernel_create include/linux/netlink.h:62 [inline]
nl_fib_lookup_init net/ipv4/fib_frontend.c:1439 [inline]
fib_net_init+0x136/0x210 net/ipv4/fib_frontend.c:1645
ops_init+0x22a/0x2e0 net/core/net_namespace.c:137
setup_net+0x83/0x210 net/core/net_namespace.c:445
copy_net_ns+0x28c/0x3b0 net/core/net_namespace.c:580
create_new_namespaces+0x20e/0x3d0 kernel/nsproxy.c:110
copy_namespaces+0x1ad/0x210 kernel/nsproxy.c:175
copy_process+0xd32/0x2000 kernel/fork.c:2184
kernel_clone+0x16c/0x5c0 kernel/fork.c:2609
__do_sys_clone kernel/fork.c:2750 [inline]
__se_sys_clone kernel/fork.c:2734 [inline]
__x64_sys_clone+0xe6/0x120 kernel/fork.c:2734
x64_sys_call+0x119c/0x3000 arch/x86/include/generated/asm/syscalls_64.h:57
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88810c48a111 of 1 bytes by task 15712 on cpu 0:
sg_fill_request_table+0x65/0x1e0 drivers/scsi/sg.c:865
sg_ioctl_common drivers/scsi/sg.c:1082 [inline]
sg_ioctl+0x6b1/0x1360 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+0x1816/0x3000 arch/x86/include/generated/asm/syscalls_64.h:17
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xd2/0x200 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: 15712 Comm: syz.5.3898 Tainted: G W syzkaller #0 PREEMPT(voluntary)
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
==================================================================


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