[moderation] [block?] KCSAN: data-race in do_mpage_readpage / set_blocksize (7)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 9ace34a8e446 Merge tag 'cgroup-for-6.7-rc4-fixes' of git:/..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11fd5ff2e80000
kernel config: https://syzkaller.appspot.com/x/.config?x=ac34c1f29a8029df
dashboard link: https://syzkaller.appspot.com/bug?extid=48231e90c63d7cc9b88d
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/955528ed37c5/disk-9ace34a8.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ed03c0892611/vmlinux-9ace34a8.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b4d56563956a/bzImage-9ace34a8.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+48231e...@syzkaller.appspotmail.com

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

write to 0xffff8881004c1d2e of 1 bytes by task 29054 on cpu 0:
set_blocksize+0x227/0x290 block/bdev.c:151
sb_set_blocksize+0x2d/0xb0 block/bdev.c:161
ext4_load_super fs/ext4/super.c:5108 [inline]
__ext4_fill_super fs/ext4/super.c:5236 [inline]
ext4_fill_super+0xad5/0x39a0 fs/ext4/super.c:5712
get_tree_bdev+0x272/0x300 fs/super.c:1598
ext4_get_tree+0x1c/0x20 fs/ext4/super.c:5744
vfs_get_tree+0x51/0x1b0 fs/super.c:1771
do_new_mount+0x203/0x660 fs/namespace.c:3337
path_mount+0x496/0xb30 fs/namespace.c:3664
do_mount fs/namespace.c:3677 [inline]
__do_sys_mount fs/namespace.c:3886 [inline]
__se_sys_mount+0x27f/0x2d0 fs/namespace.c:3863
__x64_sys_mount+0x67/0x80 fs/namespace.c:3863
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff8881004c1d2e of 1 bytes by task 3149 on cpu 1:
do_mpage_readpage+0x6c/0xd80 fs/mpage.c:162
mpage_readahead+0x1ad/0x2d0 fs/mpage.c:381
blkdev_readahead+0x1c/0x20 block/fops.c:425
read_pages+0x9f/0x530 mm/readahead.c:160
page_cache_ra_unbounded+0x2aa/0x2e0 mm/readahead.c:269
do_page_cache_ra mm/readahead.c:299 [inline]
force_page_cache_ra mm/readahead.c:330 [inline]
page_cache_sync_ra+0x24b/0x2a0 mm/readahead.c:691
page_cache_sync_readahead include/linux/pagemap.h:1283 [inline]
filemap_get_pages+0x251/0xf90 mm/filemap.c:2497
filemap_read+0x214/0x680 mm/filemap.c:2593
blkdev_read_iter+0x217/0x2c0 block/fops.c:742
call_read_iter include/linux/fs.h:2014 [inline]
new_sync_read fs/read_write.c:389 [inline]
vfs_read+0x3c0/0x590 fs/read_write.c:470
ksys_read+0xeb/0x1a0 fs/read_write.c:613
__do_sys_read fs/read_write.c:623 [inline]
__se_sys_read fs/read_write.c:621 [inline]
__x64_sys_read+0x42/0x50 fs/read_write.c:621
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x0a -> 0x0c

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 3149 Comm: udevd Not tainted 6.7.0-rc4-syzkaller-00039-g9ace34a8e446 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023
==================================================================
I/O error, dev loop4, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 2


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