KCSAN: data-race in vfs_readlink / vfs

KCSAN: data-race in vfs_readlink / vfs_unlink (2)
Status: moderation: reported on 2020/09/28 07:47
Reported-by: syzbot+d64a7b91f17b590f54c3@syzkaller.appspotmail.com
First crash: 214d, last: 4d13h

similar bugs (1):
Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in vfs_readlink / vfs_unlink				12	253d	415d	0/18	closed as invalid on 2020/06/18 14:24

Sample crash report:

ldm_validate_privheads(): Disk read failed.
 loop0: p2 < >
loop0: partition table partially beyond EOD, truncated
loop0: p2 size 2 extends beyond EOD, truncated
==================================================================
BUG: KCSAN: data-race in vfs_readlink / vfs_unlink

read-write to 0xffff888107c0c780 of 4 bytes by task 16368 on cpu 0:
 dont_mount include/linux/dcache.h:355 [inline]
 vfs_unlink+0x269/0x3b0 fs/namei.c:3837
 do_unlinkat+0x28a/0x4d0 fs/namei.c:3899
 __do_sys_unlink fs/namei.c:3945 [inline]
 __se_sys_unlink fs/namei.c:3943 [inline]
 __x64_sys_unlink+0x2c/0x30 fs/namei.c:3943
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888107c0c780 of 4 bytes by task 4889 on cpu 1:
 __d_entry_type include/linux/dcache.h:392 [inline]
 d_is_symlink include/linux/dcache.h:422 [inline]
 vfs_readlink+0x1c1/0x250 fs/namei.c:4548
 do_readlinkat+0x170/0x200 fs/stat.c:419
 __do_sys_readlink fs/stat.c:440 [inline]
 __se_sys_readlink fs/stat.c:437 [inline]
 __x64_sys_readlink+0x43/0x50 fs/stat.c:437
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 4889 Comm: systemd-udevd Not tainted 5.11.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 4889 Comm: systemd-udevd Not tainted 5.11.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x116/0x15d lib/dump_stack.c:120
 panic+0x1e7/0x5fa kernel/panic.c:231
 kcsan_report+0x67b/0x680 kernel/kcsan/report.c:634
 kcsan_setup_watchpoint+0x47b/0x4e0 kernel/kcsan/core.c:568
 __d_entry_type include/linux/dcache.h:392 [inline]
 d_is_symlink include/linux/dcache.h:422 [inline]
 vfs_readlink+0x1c1/0x250 fs/namei.c:4548
 do_readlinkat+0x170/0x200 fs/stat.c:419
 __do_sys_readlink fs/stat.c:440 [inline]
 __se_sys_readlink fs/stat.c:437 [inline]
 __x64_sys_readlink+0x43/0x50 fs/stat.c:437
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7f3464548087
Code: 73 01 c3 48 8b 0d 11 be 2b 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 59 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d e1 bd 2b 00 f7 d8 64 89 01 48
RSP: 002b:00007ffc8d849658 EFLAGS: 00000293 ORIG_RAX: 0000000000000059
RAX: ffffffffffffffda RBX: 00007ffc8d8496f0 RCX: 00007f3464548087
RDX: 0000000000000200 RSI: 00007ffc8d849800 RDI: 00007ffc8d8496d0
RBP: 00007ffc8d849c58 R08: 0000000000000001 R09: 0000000000000014
R10: 0000000000000064 R11: 0000000000000293 R12: 00007ffc8d849800
R13: 00005572adf7d010 R14: 00005572adf7d0e0 R15: 00007ffc8d8496d0
Kernel Offset: disabled
Rebooting in 86400 seconds..

Crashes (128):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	VM info	Maintainers
ci2-upstream-kcsan-gce	2021/01/22 23:45	upstream	83d09ad4	52e37319	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2021/01/22 09:26	upstream	83d09ad4	d4f4eca5	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2021/01/20 23:27	upstream	75439bc4	d4f4eca5	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2021/01/20 09:29	upstream	45dfb8a5	d4f4eca5	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2021/01/17 10:02	upstream	0da0a8a0	813be542	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2021/01/17 01:23	upstream	54c6247d	65a7a854	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2021/01/15 06:41	upstream	14662050	65a7a854	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2021/01/13 23:45	upstream	65f0d241	269d24e8	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2021/01/12 08:07	upstream	a0d54b4f	2c1f2513	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2021/01/09 23:57	upstream	2ff90100	2c1f2513	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2021/01/07 22:56	upstream	f5e6c330	c104d4a3	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2021/01/07 03:17	upstream	71c061d2	c104d4a3	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2021/01/06 12:30	upstream	9f1abbe9	fff20c29	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2021/01/03 04:31	upstream	3516bd72	79264ae3	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2021/01/02 04:18	upstream	eda809ae	79264ae3	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/12/29 19:07	upstream	dea8dcf2	80910769	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/12/29 07:31	upstream	dea8dcf2	8259d56c	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/12/26 04:25	upstream	5814bc2d	821e0b09	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/12/24 03:33	upstream	58cf05f5	c2c1d1dd	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/12/23 23:39	upstream	614cb589	c2c1d1dd	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/12/21 15:12	upstream	e37b12e4	04201c06	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/12/17 22:37	upstream	d64c6f96	04201c06	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/12/16 08:23	upstream	d01e7f10	649595c6	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/12/15 00:04	upstream	fab0fca1	97183ed7	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/12/14 04:43	upstream	ec6f5e0e	8f160dd5	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/12/12 11:10	upstream	7f376f19	bca53db9	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/12/11 14:36	upstream	33dc9614	ba24ffcd	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/12/09 22:51	upstream	ca4bbdaf	c090b4da	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/12/07 04:41	upstream	8100a580	c521566d	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/12/03 08:45	upstream	3bb61aa6	8c9190ef	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/12/02 09:11	upstream	509a1542	c42a35e9	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/11/30 23:33	upstream	b6505459	b3a34598	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/11/30 05:05	upstream	b6505459	a0092f9d	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/11/28 14:55	upstream	c84e1efa	3c7136c0	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/11/28 02:41	upstream	c84e1efa	486f93ef	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/11/27 18:07	upstream	85a2c56c	486f93ef	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/11/27 02:06	upstream	4df91062	5018c946	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/11/26 16:04	upstream	fa02fcd9	2f1cec62	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/11/24 15:19	upstream	d5beb314	1ab681a4	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/11/23 23:51	upstream	418baf2c	878fb17a	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/11/23 00:17	upstream	68d3fa23	0d27f508	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/11/21 20:27	upstream	27bba9c5	c7ec2d19	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/11/18 21:21	upstream	c2e7554e	0767f13f	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/11/16 09:44	upstream	09162bc3	1bf9a662	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/11/15 19:25	upstream	0062442e	1bf9a662	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/11/15 11:46	upstream	e28c0d7c	1bf9a662	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/11/14 16:24	upstream	f01c30de	1bf9a662	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/11/14 01:11	upstream	9e6a39ea	1bf9a662	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/09/23 22:04	upstream	805c6d3c	54289b08	.config	log	report	info	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
ci2-upstream-kcsan-gce	2020/06/26 15:34	upstream	4a21185c	9506ea6d	.config	log	report		linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk