[moderation] [mm?] KCSAN: data-race in _copy_from_iter / _copy_from_iter (4)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: ff7afaeca1a1 Merge tag 'nfs-for-6.12-3' of git://git.linux..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=141cad87980000
kernel config: https://syzkaller.appspot.com/x/.config?x=8028551073794907
dashboard link: https://syzkaller.appspot.com/bug?extid=0fc60bb395892ced5ddf
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [ak...@linux-foundation.org linux-...@vger.kernel.org linu...@kvack.org]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/c03b87208cde/disk-ff7afaec.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/1237785742b7/vmlinux-ff7afaec.xz
kernel image: https://storage.googleapis.com/syzbot-assets/1c291ff2dd7b/bzImage-ff7afaec.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+0fc60b...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in _copy_from_iter / _copy_from_iter

write to 0xffff88814b576000 of 4096 bytes by task 32191 on cpu 0:
instrument_copy_from_user_before include/linux/instrumented.h:130 [inline]
copy_from_user_iter lib/iov_iter.c:54 [inline]
iterate_ubuf include/linux/iov_iter.h:30 [inline]
iterate_and_advance2 include/linux/iov_iter.h:300 [inline]
iterate_and_advance include/linux/iov_iter.h:328 [inline]
__copy_from_iter lib/iov_iter.c:249 [inline]
_copy_from_iter+0x133/0xd00 lib/iov_iter.c:260
copy_page_from_iter+0x14f/0x280 lib/iov_iter.c:422
process_vm_rw_pages mm/process_vm_access.c:43 [inline]
process_vm_rw_single_vec mm/process_vm_access.c:118 [inline]
process_vm_rw_core mm/process_vm_access.c:216 [inline]
process_vm_rw+0x5d6/0x8c0 mm/process_vm_access.c:284
__do_sys_process_vm_writev mm/process_vm_access.c:304 [inline]
__se_sys_process_vm_writev mm/process_vm_access.c:299 [inline]
__x64_sys_process_vm_writev+0x7a/0x90 mm/process_vm_access.c:299
x64_sys_call+0x1a4/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:312
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

write to 0xffff88814b576000 of 4096 bytes by task 32193 on cpu 1:
instrument_copy_from_user_before include/linux/instrumented.h:130 [inline]
copy_from_user_iter lib/iov_iter.c:54 [inline]
iterate_ubuf include/linux/iov_iter.h:30 [inline]
iterate_and_advance2 include/linux/iov_iter.h:300 [inline]
iterate_and_advance include/linux/iov_iter.h:328 [inline]
__copy_from_iter lib/iov_iter.c:249 [inline]
_copy_from_iter+0x133/0xd00 lib/iov_iter.c:260
copy_page_from_iter+0x14f/0x280 lib/iov_iter.c:422
process_vm_rw_pages mm/process_vm_access.c:43 [inline]
process_vm_rw_single_vec mm/process_vm_access.c:118 [inline]
process_vm_rw_core mm/process_vm_access.c:216 [inline]
process_vm_rw+0x5d6/0x8c0 mm/process_vm_access.c:284
__do_sys_process_vm_writev mm/process_vm_access.c:304 [inline]
__se_sys_process_vm_writev mm/process_vm_access.c:299 [inline]
__x64_sys_process_vm_writev+0x7a/0x90 mm/process_vm_access.c:299
x64_sys_call+0x1a4/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:312
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 32193 Comm: syz.8.10251 Not tainted 6.12.0-rc6-syzkaller-00110-gff7afaeca1a1 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
==================================================================


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.