[moderation] [block?] KCSAN: data-race in do_mpage_readpage / set_blocksize (8)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 626737a5791b Merge tag 'pinctrl-v6.10-2' of git://git.kern..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=160c6fb1980000
kernel config: https://syzkaller.appspot.com/x/.config?x=7e87b541dc1fc960
dashboard link: https://syzkaller.appspot.com/bug?extid=2968e9a3ea1930bdb425
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [ax...@kernel.dk 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/ee4c67adef4f/disk-626737a5.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/124b0d3318d3/vmlinux-626737a5.xz
kernel image: https://storage.googleapis.com/syzbot-assets/8acf9961638a/bzImage-626737a5.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+2968e9...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in do_mpage_readpage / set_blocksize

write to 0xffff888100630a76 of 1 bytes by task 3367 on cpu 1:
set_blocksize+0x24c/0x2b0 block/bdev.c:171
sb_set_blocksize block/bdev.c:181 [inline]
sb_min_blocksize+0x8c/0x110 block/bdev.c:197
fat_fill_super+0xf42/0x2880 fs/fat/inode.c:1653
vfat_fill_super+0x30/0x40 fs/fat/namei_vfat.c:1200
mount_bdev+0x152/0x1e0 fs/super.c:1659
vfat_mount+0x31/0x40 fs/fat/namei_vfat.c:1207
legacy_get_tree+0x77/0xd0 fs/fs_context.c:662
vfs_get_tree+0x56/0x1d0 fs/super.c:1780
do_new_mount+0x227/0x690 fs/namespace.c:3352
path_mount+0x49b/0xb30 fs/namespace.c:3679
do_mount fs/namespace.c:3692 [inline]
__do_sys_mount fs/namespace.c:3898 [inline]
__se_sys_mount+0x27f/0x2d0 fs/namespace.c:3875
__x64_sys_mount+0x67/0x80 fs/namespace.c:3875
x64_sys_call+0x25c9/0x2d70 arch/x86/include/generated/asm/syscalls_64.h:166
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

read to 0xffff888100630a76 of 1 bytes by task 3158 on cpu 0:
do_mpage_readpage+0x55/0xcb0 fs/mpage.c:162
mpage_readahead+0x1ad/0x2d0 fs/mpage.c:381
blkdev_readahead+0x1c/0x30 block/fops.c:438
read_pages+0xa0/0x540 mm/readahead.c:160
page_cache_ra_unbounded+0x285/0x2e0 mm/readahead.c:273
do_page_cache_ra mm/readahead.c:303 [inline]
force_page_cache_ra+0x18e/0x1d0 mm/readahead.c:334
page_cache_sync_ra+0xcc/0xf0 mm/readahead.c:692
page_cache_sync_readahead include/linux/pagemap.h:1306 [inline]
filemap_get_pages+0x252/0xfb0 mm/filemap.c:2529
filemap_read+0x21c/0x690 mm/filemap.c:2625
blkdev_read_iter+0x217/0x2c0 block/fops.c:749
new_sync_read fs/read_write.c:395 [inline]
vfs_read+0x5e6/0x6e0 fs/read_write.c:476
ksys_read+0xeb/0x1b0 fs/read_write.c:619
__do_sys_read fs/read_write.c:629 [inline]
__se_sys_read fs/read_write.c:627 [inline]
__x64_sys_read+0x42/0x50 fs/read_write.c:627
x64_sys_call+0x27e5/0x2d70 arch/x86/include/generated/asm/syscalls_64.h:1
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

value changed: 0x0c -> 0x09

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 3158 Comm: udevd Not tainted 6.10.0-rc5-syzkaller-00012-g626737a5791b #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
==================================================================
udevd (3158) used greatest stack depth: 10744 bytes left


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