[moderation] [rdma?] KCSAN: data-race in addr_handler / ucma_query

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 24d479d26b25 Linux 6.19-rc6
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=171cce3a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=676c6f0212d0c041
dashboard link: https://syzkaller.appspot.com/bug?extid=4cb1ac8bd5fbaae0e894
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
CC: [j...@ziepe.ca le...@kernel.org linux-...@vger.kernel.org linux...@vger.kernel.org]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/e47d2b960e97/disk-24d479d2.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/75c59e1fc76a/vmlinux-24d479d2.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e42579adf478/bzImage-24d479d2.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+4cb1ac...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in addr_handler / ucma_query

write to 0xffff88812ddf7820 of 28 bytes by task 7338 on cpu 1:
addr_handler+0x10d/0x2f0 drivers/infiniband/core/cma.c:3523
process_one_req+0x1f5/0x2e0 drivers/infiniband/core/addr.c:622
process_one_work kernel/workqueue.c:3257 [inline]
process_scheduled_works+0x4cd/0x9d0 kernel/workqueue.c:3340
worker_thread+0x581/0x770 kernel/workqueue.c:3421
kthread+0x488/0x510 kernel/kthread.c:463
ret_from_fork+0x148/0x280 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

read to 0xffff88812ddf7820 of 28 bytes by task 13116 on cpu 0:
ucma_query_addr drivers/infiniband/core/ucma.c:925 [inline]
ucma_query+0x773/0xe70 drivers/infiniband/core/ucma.c:1081
ucma_write+0x1c9/0x260 drivers/infiniband/core/ucma.c:1856
do_loop_readv_writev fs/read_write.c:850 [inline]
vfs_writev+0x42b/0x900 fs/read_write.c:1059
do_writev+0xe9/0x210 fs/read_write.c:1103
__do_sys_writev fs/read_write.c:1171 [inline]
__se_sys_writev fs/read_write.c:1168 [inline]
__x64_sys_writev+0x45/0x50 fs/read_write.c:1168
x64_sys_call+0x1ba5/0x3000 arch/x86/include/generated/asm/syscalls_64.h:21
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xc0/0x2a0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 13116 Comm: syz.0.2525 Tainted: G W syzkaller #0 PREEMPT(voluntary)
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
==================================================================


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