[moderation] [fs?] [mm?] KCSAN: data-race in __filemap_add_folio / invalidate_bdev (9)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 7595b66ae9de Merge tag 'selinux-pr-20250624' of git://git...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14eb6f0c580000
kernel config: https://syzkaller.appspot.com/x/.config?x=39acdbb3c95d37e5
dashboard link: https://syzkaller.appspot.com/bug?extid=51340a329fdcf1a5967c
compiler: Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6
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/95c3cc8c3471/disk-7595b66a.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/40d1c5a0506e/vmlinux-7595b66a.xz
kernel image: https://storage.googleapis.com/syzbot-assets/636329b317bc/bzImage-7595b66a.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+51340a...@syzkaller.appspotmail.com

netlink: 44 bytes leftover after parsing attributes in process `syz.6.13394'.
loop6: detected capacity change from 0 to 512
EXT4-fs: Ignoring removed bh option
EXT4-fs: Mount option(s) incompatible with ext3
==================================================================
BUG: KCSAN: data-race in __filemap_add_folio / invalidate_bdev

read-write to 0xffff88811c84ca30 of 8 bytes by task 23859 on cpu 0:
__filemap_add_folio+0x5b9/0x7d0 mm/filemap.c:928
filemap_add_folio+0x98/0x1b0 mm/filemap.c:969
page_cache_ra_unbounded+0x1f3/0x380 mm/readahead.c:275
do_page_cache_ra mm/readahead.c:327 [inline]
force_page_cache_ra mm/readahead.c:356 [inline]
page_cache_sync_ra+0x256/0x6a0 mm/readahead.c:575
filemap_get_pages+0x2d0/0x1150 mm/filemap.c:2602
filemap_read+0x231/0xa00 mm/filemap.c:2711
blkdev_read_iter+0x22d/0x2e0 block/fops.c:833
new_sync_read fs/read_write.c:491 [inline]
vfs_read+0x5cd/0x6f0 fs/read_write.c:572
ksys_read+0xda/0x1a0 fs/read_write.c:715
__do_sys_read fs/read_write.c:724 [inline]
__se_sys_read fs/read_write.c:722 [inline]
__x64_sys_read+0x40/0x50 fs/read_write.c:722
x64_sys_call+0x2d77/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:1
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 0xffff88811c84ca30 of 8 bytes by task 9973 on cpu 1:
invalidate_bdev+0x25/0x70 block/bdev.c:99
__ext4_fill_super fs/ext4/super.c:5699 [inline]
ext4_fill_super+0x2a6e/0x34e0 fs/ext4/super.c:5724
get_tree_bdev_flags+0x291/0x300 fs/super.c:1681
get_tree_bdev+0x1f/0x30 fs/super.c:1704
ext4_get_tree+0x1c/0x30 fs/ext4/super.c:5756
vfs_get_tree+0x54/0x1d0 fs/super.c:1804
do_new_mount+0x207/0x680 fs/namespace.c:3885
path_mount+0x4a4/0xb20 fs/namespace.c:4209
do_mount fs/namespace.c:4222 [inline]
__do_sys_mount fs/namespace.c:4433 [inline]
__se_sys_mount+0x28f/0x2e0 fs/namespace.c:4410
__x64_sys_mount+0x67/0x80 fs/namespace.c:4410
x64_sys_call+0xd36/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:166
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: 0x0000000000000001 -> 0x0000000000000002

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 9973 Comm: syz.6.13394 Not tainted 6.16.0-rc3-syzkaller-00044-g7595b66ae9de #0 PREEMPT(voluntary)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
==================================================================


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[syzbot]

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