[moderation] [fs?] [mm?] KCSAN: data-race in ondemand_readahead / ondemand_readahead (11)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 0bbac3facb5d Linux 6.9-rc4
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10d4f77d180000
kernel config: https://syzkaller.appspot.com/x/.config?x=eaea34ec4c9b6fb6
dashboard link: https://syzkaller.appspot.com/bug?extid=701803384e5bfe149765
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [ak...@linux-foundation.org linux-...@vger.kernel.org linux-...@vger.kernel.org linu...@kvack.org wi...@infradead.org]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/5e85356d4cd6/disk-0bbac3fa.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/9bc6a51e45e8/vmlinux-0bbac3fa.xz
kernel image: https://storage.googleapis.com/syzbot-assets/7a1ec327fc6a/bzImage-0bbac3fa.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+701803...@syzkaller.appspotmail.com

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

read to 0xffff888115c4dc78 of 8 bytes by task 6619 on cpu 0:
ondemand_readahead+0x133/0x6c0 mm/readahead.c:573
page_cache_async_ra+0x94/0xa0 mm/readahead.c:710
do_async_mmap_readahead mm/filemap.c:3179 [inline]
filemap_fault+0x3da/0xc70 mm/filemap.c:3275
__do_fault+0xb6/0x200 mm/memory.c:4531
do_read_fault mm/memory.c:4894 [inline]
do_fault mm/memory.c:5024 [inline]
do_pte_missing mm/memory.c:3880 [inline]
handle_pte_fault mm/memory.c:5300 [inline]
__handle_mm_fault mm/memory.c:5441 [inline]
handle_mm_fault+0xdbf/0x27e0 mm/memory.c:5606
do_user_addr_fault arch/x86/mm/fault.c:1413 [inline]
handle_page_fault arch/x86/mm/fault.c:1505 [inline]
exc_page_fault+0x2f5/0x6d0 arch/x86/mm/fault.c:1563
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
rep_movs_alternative+0x30/0x70 arch/x86/lib/copy_user_64.S:50
copy_user_generic arch/x86/include/asm/uaccess_64.h:110 [inline]
raw_copy_from_user arch/x86/include/asm/uaccess_64.h:125 [inline]
_copy_from_user+0x80/0xd0 lib/usercopy.c:23
copy_from_user include/linux/uaccess.h:183 [inline]
copy_msghdr_from_user+0x54/0x2a0 net/socket.c:2514
recvmsg_copy_msghdr net/socket.c:2769 [inline]
___sys_recvmsg net/socket.c:2841 [inline]
do_recvmmsg+0x290/0x720 net/socket.c:2939
__sys_recvmmsg net/socket.c:3018 [inline]
__do_sys_recvmmsg net/socket.c:3041 [inline]
__se_sys_recvmmsg net/socket.c:3034 [inline]
__x64_sys_recvmmsg+0xe2/0x170 net/socket.c:3034
x64_sys_call+0xda3/0x2d30 arch/x86/include/generated/asm/syscalls_64.h:300
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

write to 0xffff888115c4dc78 of 8 bytes by task 6620 on cpu 1:
ondemand_readahead+0x58f/0x6c0 mm/readahead.c:599
page_cache_async_ra+0x94/0xa0 mm/readahead.c:710
do_async_mmap_readahead mm/filemap.c:3179 [inline]
filemap_fault+0x3da/0xc70 mm/filemap.c:3275
__do_fault+0xb6/0x200 mm/memory.c:4531
do_read_fault mm/memory.c:4894 [inline]
do_fault mm/memory.c:5024 [inline]
do_pte_missing mm/memory.c:3880 [inline]
handle_pte_fault mm/memory.c:5300 [inline]
__handle_mm_fault mm/memory.c:5441 [inline]
handle_mm_fault+0xdbf/0x27e0 mm/memory.c:5606
do_user_addr_fault arch/x86/mm/fault.c:1413 [inline]
handle_page_fault arch/x86/mm/fault.c:1505 [inline]
exc_page_fault+0x2f5/0x6d0 arch/x86/mm/fault.c:1563
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
fault_in_readable+0xf8/0x1b0
fault_in_iov_iter_readable+0x152/0x190 lib/iov_iter.c:94
generic_perform_write+0x106/0x410 mm/filemap.c:3964
ext4_buffered_write_iter+0x1f6/0x380 fs/ext4/file.c:299
ext4_file_write_iter+0x29f/0xe30
call_write_iter include/linux/fs.h:2110 [inline]
new_sync_write fs/read_write.c:497 [inline]
vfs_write+0x771/0x8e0 fs/read_write.c:590
ksys_write+0xeb/0x1b0 fs/read_write.c:643
__do_sys_write fs/read_write.c:655 [inline]
__se_sys_write fs/read_write.c:652 [inline]
__x64_sys_write+0x42/0x50 fs/read_write.c:652
x64_sys_call+0x27b7/0x2d30 arch/x86/include/generated/asm/syscalls_64.h:2
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000000000000aa -> 0x000000000000012f

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 6620 Comm: syz-executor.3 Not tainted 6.9.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
==================================================================


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