Hello,
syzbot found the following crash on:
HEAD commit: 40959e34 kcsan: Avoid blocking producers in prepare_report()
git tree:
https://github.com/google/ktsan.git kcsan
console output:
https://syzkaller.appspot.com/x/log.txt?x=1028ea83e00000
kernel config:
https://syzkaller.appspot.com/x/.config?x=1ab2c758651b11f6
dashboard link:
https://syzkaller.appspot.com/bug?extid=41525f42a971ade8fd71
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
CC: [
adilger...@dilger.ca linux...@vger.kernel.org linux-...@vger.kernel.org ty...@mit.edu el...@google.com]
Unfortunately, I don't have any reproducer for this crash yet.
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by:
syzbot+41525f...@syzkaller.appspotmail.com
==================================================================
BUG: KCSAN: data-race in ext4_mb_good_group / mb_free_blocks
write to 0xffff88821a408018 of 4 bytes by task 7800 on cpu 1:
mb_free_blocks+0x4a0/0xef0 fs/ext4/mballoc.c:1468
ext4_free_blocks+0x8ad/0x1540 fs/ext4/mballoc.c:4909
ext4_remove_blocks fs/ext4/extents.c:2646 [inline]
ext4_ext_rm_leaf fs/ext4/extents.c:2812 [inline]
ext4_ext_remove_space+0x1862/0x2bf0 fs/ext4/extents.c:3059
ext4_ext_truncate+0x11a/0x120 fs/ext4/extents.c:4579
ext4_truncate+0x5c8/0x9d0 fs/ext4/inode.c:4198
ext4_evict_inode+0x5e6/0xa40 fs/ext4/inode.c:270
evict+0x238/0x3f0 fs/inode.c:575
iput_final fs/inode.c:1571 [inline]
iput+0x36a/0x4d0 fs/inode.c:1597
dentry_unlink_inode+0x272/0x2e0 fs/dcache.c:374
d_delete fs/dcache.c:2451 [inline]
d_delete+0xca/0xe0 fs/dcache.c:2440
vfs_rmdir fs/namei.c:3966 [inline]
vfs_rmdir+0x2d3/0x2f0 fs/namei.c:3931
do_rmdir+0x2e9/0x320 fs/namei.c:4014
__do_sys_rmdir fs/namei.c:4032 [inline]
__se_sys_rmdir fs/namei.c:4030 [inline]
__x64_sys_rmdir+0x2c/0x40 fs/namei.c:4030
do_syscall_64+0xc7/0x390 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x44/0xa9
read to 0xffff88821a408018 of 4 bytes by task 7796 on cpu 0:
ext4_mb_good_group+0x1be/0x400 fs/ext4/mballoc.c:2059
ext4_mb_regular_allocator+0x6ba/0x990 fs/ext4/mballoc.c:2183
ext4_mb_new_blocks+0xfce/0x1ea0 fs/ext4/mballoc.c:4543
ext4_ext_map_blocks+0x1a5c/0x20f0 fs/ext4/extents.c:4440
ext4_map_blocks+0x230/0xcf0 fs/ext4/inode.c:622
ext4_getblk+0x82/0x380 fs/ext4/inode.c:826
ext4_bread+0x47/0x200 fs/ext4/inode.c:876
ext4_append+0xc0/0x1e0 fs/ext4/namei.c:67
ext4_init_new_dir fs/ext4/namei.c:2747 [inline]
ext4_mkdir+0x401/0x820 fs/ext4/namei.c:2792
vfs_mkdir+0x281/0x390 fs/namei.c:3889
do_mkdirat+0x1b5/0x200 fs/namei.c:3912
__do_sys_mkdir fs/namei.c:3928 [inline]
__se_sys_mkdir fs/namei.c:3926 [inline]
__x64_sys_mkdir+0x3d/0x50 fs/namei.c:3926
do_syscall_64+0xc7/0x390 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 7796 Comm: syz-executor.2 Not tainted 5.6.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================
---
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