[moderation] [ext4?] KCSAN: data-race in has_bh_in_lru / invalidate_bh_lru (6)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 7d4050728c83 Merge tag 'vfs-6.13-rc1.fixes' of git://git.k..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15c5f778580000
kernel config: https://syzkaller.appspot.com/x/.config?x=91c30f6c13debe26
dashboard link: https://syzkaller.appspot.com/bug?extid=80bd9e218b2e56fdf6ed
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [adilger...@dilger.ca linux...@vger.kernel.org linux-...@vger.kernel.org ty...@mit.edu]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/e649e067ed16/disk-7d405072.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/82e3a6c9d09d/vmlinux-7d405072.xz
kernel image: https://storage.googleapis.com/syzbot-assets/5189e2f53568/bzImage-7d405072.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+80bd9e...@syzkaller.appspotmail.com

netlink: 28 bytes leftover after parsing attributes in process `syz.9.2011'.
loop9: detected capacity change from 0 to 256
==================================================================
BUG: KCSAN: data-race in has_bh_in_lru / invalidate_bh_lru

write to 0xffff888237d2ba28 of 8 bytes by task 12727 on cpu 1:
__invalidate_bh_lrus fs/buffer.c:1499 [inline]
invalidate_bh_lru+0x8b/0xf0 fs/buffer.c:1511
csd_do_func kernel/smp.c:134 [inline]
smp_call_function_many_cond+0x690/0xc20 kernel/smp.c:875
on_each_cpu_cond_mask+0x3c/0x90 kernel/smp.c:1051
on_each_cpu_cond include/linux/smp.h:105 [inline]
invalidate_bh_lrus+0x2a/0x30 fs/buffer.c:1530
invalidate_bdev+0x42/0x70 block/bdev.c:100
__ext4_fill_super fs/ext4/super.c:5708 [inline]
ext4_fill_super+0x6f3/0x3a10 fs/ext4/super.c:5733
get_tree_bdev_flags+0x29f/0x310 fs/super.c:1636
get_tree_bdev+0x1f/0x30 fs/super.c:1659
ext4_get_tree+0x1c/0x30 fs/ext4/super.c:5765
vfs_get_tree+0x56/0x1e0 fs/super.c:1814
do_new_mount+0x227/0x690 fs/namespace.c:3507
path_mount+0x49b/0xb30 fs/namespace.c:3834
do_mount fs/namespace.c:3847 [inline]
__do_sys_mount fs/namespace.c:4057 [inline]
__se_sys_mount+0x27c/0x2d0 fs/namespace.c:4034
__x64_sys_mount+0x67/0x80 fs/namespace.c:4034
x64_sys_call+0x2c84/0x2dc0 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 0xffff888237d2ba28 of 8 bytes by task 12736 on cpu 0:
has_bh_in_lru+0x35/0x1f0 fs/buffer.c:1521
smp_call_function_many_cond+0x2d5/0xc20 kernel/smp.c:837
on_each_cpu_cond_mask+0x3c/0x90 kernel/smp.c:1051
on_each_cpu_cond include/linux/smp.h:105 [inline]
invalidate_bh_lrus+0x2a/0x30 fs/buffer.c:1530
kill_bdev block/bdev.c:90 [inline]
set_blocksize+0x24c/0x270 block/bdev.c:173
sb_set_blocksize+0x2c/0xb0 block/bdev.c:182
fat_fill_super+0x99d/0x1bf0 fs/fat/inode.c:1629
vfat_fill_super+0x24/0x30 fs/fat/namei_vfat.c:1200
get_tree_bdev_flags+0x29f/0x310 fs/super.c:1636
get_tree_bdev+0x1f/0x30 fs/super.c:1659
vfat_get_tree+0x1c/0x30 fs/fat/namei_vfat.c:1205
vfs_get_tree+0x56/0x1e0 fs/super.c:1814
do_new_mount+0x227/0x690 fs/namespace.c:3507
path_mount+0x49b/0xb30 fs/namespace.c:3834
do_mount fs/namespace.c:3847 [inline]
__do_sys_mount fs/namespace.c:4057 [inline]
__se_sys_mount+0x27c/0x2d0 fs/namespace.c:4034
__x64_sys_mount+0x67/0x80 fs/namespace.c:4034
x64_sys_call+0x2c84/0x2dc0 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

value changed: 0xffff88810447f138 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 12736 Comm: syz.9.2011 Not tainted 6.12.0-syzkaller-10313-g7d4050728c83 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
==================================================================
FAT-fs (loop9): Directory bread(block 64) failed
FAT-fs (loop9): Directory bread(block 65) failed
FAT-fs (loop9): Directory bread(block 66) failed
FAT-fs (loop9): Directory bread(block 67) failed
FAT-fs (loop9): Directory bread(block 68) failed
FAT-fs (loop9): Directory bread(block 69) failed
FAT-fs (loop9): Directory bread(block 70) failed
FAT-fs (loop9): Directory bread(block 71) failed
FAT-fs (loop9): Directory bread(block 72) failed
FAT-fs (loop9): Directory bread(block 73) failed


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[syzbot]

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