[moderation] [mm?] KCSAN: data-race in _copy_from_iter / _copy_to_iter

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 98b1cc82c4af Linux 6.7-rc2
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=167f10f0e80000
kernel config: https://syzkaller.appspot.com/x/.config?x=8c1151391aefc0c3
dashboard link: https://syzkaller.appspot.com/bug?extid=ed284c457f2f9b839aac
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/b63fb347c844/disk-98b1cc82.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a75961292759/vmlinux-98b1cc82.xz
kernel image: https://storage.googleapis.com/syzbot-assets/52ef29cc01f9/bzImage-98b1cc82.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ed284c...@syzkaller.appspotmail.com

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

read to 0xffff88814ee06000 of 4096 bytes by task 16629 on cpu 0:
instrument_copy_to_user include/linux/instrumented.h:113 [inline]
copy_to_user_iter lib/iov_iter.c:24 [inline]
iterate_iovec include/linux/iov_iter.h:51 [inline]
iterate_and_advance2 include/linux/iov_iter.h:247 [inline]
iterate_and_advance include/linux/iov_iter.h:271 [inline]
_copy_to_iter+0x2aa/0xb20 lib/iov_iter.c:186
copy_page_to_iter+0x171/0x2b0 lib/iov_iter.c:381
process_vm_rw_pages mm/process_vm_access.c:45 [inline]
process_vm_rw_single_vec mm/process_vm_access.c:117 [inline]
process_vm_rw_core mm/process_vm_access.c:215 [inline]
process_vm_rw+0x5ed/0x8c0 mm/process_vm_access.c:283
__do_sys_process_vm_readv mm/process_vm_access.c:295 [inline]
__se_sys_process_vm_readv mm/process_vm_access.c:291 [inline]
__x64_sys_process_vm_readv+0x7a/0x90 mm/process_vm_access.c:291
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x63/0x6b

write to 0xffff88814ee06000 of 4096 bytes by task 16612 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_iovec include/linux/iov_iter.h:51 [inline]
iterate_and_advance2 include/linux/iov_iter.h:247 [inline]
iterate_and_advance include/linux/iov_iter.h:271 [inline]
__copy_from_iter lib/iov_iter.c:268 [inline]
_copy_from_iter+0x2e7/0xb60 lib/iov_iter.c:279
copy_page_from_iter+0x14f/0x280 lib/iov_iter.c:441
process_vm_rw_pages mm/process_vm_access.c:43 [inline]
process_vm_rw_single_vec mm/process_vm_access.c:117 [inline]
process_vm_rw_core mm/process_vm_access.c:215 [inline]
process_vm_rw+0x5d3/0x8c0 mm/process_vm_access.c:283
__do_sys_process_vm_writev mm/process_vm_access.c:303 [inline]
__se_sys_process_vm_writev mm/process_vm_access.c:298 [inline]
__x64_sys_process_vm_writev+0x7a/0x90 mm/process_vm_access.c:298
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x63/0x6b

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 16612 Comm: syz-executor.2 Not tainted 6.7.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023
==================================================================


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[syzbot]

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