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KCSAN: data-race in ext4_xattr_block_set / mb_cache_entry_touch

Status: auto-closed as invalid on 2020/02/07 14:57
Subsystems: ext4
[Documentation on labels]
First crash: 1601d, last: 1601d

Sample crash report:
==================================================================
BUG: KCSAN: data-race in ext4_xattr_block_set / mb_cache_entry_touch

read to 0xffff88812533e338 of 1 bytes by task 11586 on cpu 0:
 ext4_xattr_block_set+0xfc6/0x1cf0 fs/ext4/xattr.c:2017
 ext4_xattr_set_handle+0x969/0xcc0 fs/ext4/xattr.c:2404
 __ext4_set_acl+0x25a/0x360 fs/ext4/acl.c:214
 ext4_init_acl+0x98/0x200 fs/ext4/acl.c:285
 __ext4_new_inode+0x2775/0x2ec0 fs/ext4/ialloc.c:1156
 ext4_mkdir+0x289/0x820 fs/ext4/namei.c:2763
 vfs_mkdir+0x283/0x390 fs/namei.c:3807
 ovl_do_mkdir fs/overlayfs/overlayfs.h:125 [inline]
 ovl_mkdir_real fs/overlayfs/dir.c:122 [inline]
 ovl_create_real+0x1ec/0x2c0 fs/overlayfs/dir.c:169
 ovl_workdir_create+0x299/0x3f0 fs/overlayfs/super.c:650
 ovl_make_workdir fs/overlayfs/super.c:1088 [inline]
 ovl_get_workdir fs/overlayfs/super.c:1191 [inline]
 ovl_fill_super+0xc27/0x2736 fs/overlayfs/super.c:1611
 mount_nodev+0x6b/0xf0 fs/super.c:1461
 ovl_mount+0x36/0x50 fs/overlayfs/super.c:1712
 legacy_get_tree+0x7e/0xf0 fs/fs_context.c:647
 vfs_get_tree+0x56/0x1a0 fs/super.c:1545
 do_new_mount fs/namespace.c:2822 [inline]
 do_mount+0x1004/0x14f0 fs/namespace.c:3142
 ksys_mount+0xe8/0x160 fs/namespace.c:3351
 __do_sys_mount fs/namespace.c:3365 [inline]
 __se_sys_mount fs/namespace.c:3362 [inline]
 __x64_sys_mount+0x70/0x90 fs/namespace.c:3362
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff88812533e338 of 1 bytes by task 11580 on cpu 1:
 mb_cache_entry_touch+0x1f/0x30 fs/mbcache.c:266
 ext4_xattr_block_set+0x1321/0x1cf0 fs/ext4/xattr.c:2046
 ext4_xattr_set_handle+0x969/0xcc0 fs/ext4/xattr.c:2404
 __ext4_set_acl+0x25a/0x360 fs/ext4/acl.c:214
 ext4_init_acl+0x98/0x200 fs/ext4/acl.c:285
 __ext4_new_inode+0x2775/0x2ec0 fs/ext4/ialloc.c:1156
 ext4_mkdir+0x289/0x820 fs/ext4/namei.c:2763
 vfs_mkdir+0x283/0x390 fs/namei.c:3807
 ovl_do_mkdir fs/overlayfs/overlayfs.h:125 [inline]
 ovl_mkdir_real fs/overlayfs/dir.c:122 [inline]
 ovl_create_real+0x1ec/0x2c0 fs/overlayfs/dir.c:169
 ovl_workdir_create+0x299/0x3f0 fs/overlayfs/super.c:650
 ovl_make_workdir fs/overlayfs/super.c:1088 [inline]
 ovl_get_workdir fs/overlayfs/super.c:1191 [inline]
 ovl_fill_super+0xc27/0x2736 fs/overlayfs/super.c:1611
 mount_nodev+0x6b/0xf0 fs/super.c:1461
 ovl_mount+0x36/0x50 fs/overlayfs/super.c:1712
 legacy_get_tree+0x7e/0xf0 fs/fs_context.c:647
 vfs_get_tree+0x56/0x1a0 fs/super.c:1545
 do_new_mount fs/namespace.c:2822 [inline]
 do_mount+0x1004/0x14f0 fs/namespace.c:3142
 ksys_mount+0xe8/0x160 fs/namespace.c:3351
 __do_sys_mount fs/namespace.c:3365 [inline]
 __se_sys_mount fs/namespace.c:3362 [inline]
 __x64_sys_mount+0x70/0x90 fs/namespace.c:3362
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 11580 Comm: syz-executor.1 Not tainted 5.4.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2019/11/29 14:49 https://github.com/google/ktsan.git kcsan ef798c30ba4e 4f7e1d0f .config console log report ci2-upstream-kcsan-gce
* Struck through repros no longer work on HEAD.