* KMSAN: uninit-value in f2fs_lookup
@ 2020-09-25 5:18 syzbot
2020-09-25 9:06 ` [f2fs-dev] " Chao Yu
0 siblings, 1 reply; 7+ messages in thread
From: syzbot @ 2020-09-25 5:18 UTC (permalink / raw)
To: chao, glider, jaegeuk, linux-f2fs-devel, linux-kernel, syzkaller-bugs
Hello,
syzbot found the following issue on:
HEAD commit: c5a13b33 kmsan: clang-format core
git tree: https://github.com/google/kmsan.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=14f5b19b900000
kernel config: https://syzkaller.appspot.com/x/.config?x=20f149ad694ba4be
dashboard link: https://syzkaller.appspot.com/bug?extid=0eac6f0bbd558fd866d7
compiler: clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81)
userspace arch: i386
Unfortunately, I don't have any reproducer for this issue yet.
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+0eac6f0bbd558fd866d7@syzkaller.appspotmail.com
=====================================================
BUG: KMSAN: uninit-value in f2fs_lookup+0xe05/0x1a80 fs/f2fs/namei.c:503
CPU: 0 PID: 20216 Comm: syz-executor.5 Not tainted 5.9.0-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:77 [inline]
dump_stack+0x21c/0x280 lib/dump_stack.c:118
kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:122
__msan_warning+0x58/0xa0 mm/kmsan/kmsan_instr.c:219
f2fs_lookup+0xe05/0x1a80 fs/f2fs/namei.c:503
lookup_open fs/namei.c:3082 [inline]
open_last_lookups fs/namei.c:3177 [inline]
path_openat+0x2729/0x6a90 fs/namei.c:3365
do_filp_open+0x2b8/0x710 fs/namei.c:3395
do_sys_openat2+0xa88/0x1140 fs/open.c:1168
do_sys_open fs/open.c:1184 [inline]
__do_compat_sys_openat fs/open.c:1242 [inline]
__se_compat_sys_openat+0x2a4/0x310 fs/open.c:1240
__ia32_compat_sys_openat+0x56/0x70 fs/open.c:1240
do_syscall_32_irqs_on arch/x86/entry/common.c:80 [inline]
__do_fast_syscall_32+0x129/0x180 arch/x86/entry/common.c:139
do_fast_syscall_32+0x6a/0xc0 arch/x86/entry/common.c:162
do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:205
entry_SYSENTER_compat_after_hwframe+0x4d/0x5c
RIP: 0023:0xf7f73549
Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 002b:00000000f554c0cc EFLAGS: 00000296 ORIG_RAX: 0000000000000127
RAX: ffffffffffffffda RBX: 00000000ffffff9c RCX: 0000000020000980
RDX: 000000000002f042 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
Local variable ----page@f2fs_lookup created at:
f2fs_lookup+0x8f/0x1a80 fs/f2fs/namei.c:477
f2fs_lookup+0x8f/0x1a80 fs/f2fs/namei.c:477
=====================================================
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [f2fs-dev] KMSAN: uninit-value in f2fs_lookup
2020-09-25 5:18 KMSAN: uninit-value in f2fs_lookup syzbot
@ 2020-09-25 9:06 ` Chao Yu
2020-09-25 10:57 ` Dan Carpenter
2020-09-25 16:38 ` Eric Biggers
0 siblings, 2 replies; 7+ messages in thread
From: Chao Yu @ 2020-09-25 9:06 UTC (permalink / raw)
To: syzbot, chao, glider, jaegeuk, linux-f2fs-devel, linux-kernel,
syzkaller-bugs
Hi,
I don't see any problem here, thanks for your report. :)
Thanks,
On 2020/9/25 13:18, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: c5a13b33 kmsan: clang-format core
> git tree: https://github.com/google/kmsan.git master
> console output: https://syzkaller.appspot.com/x/log.txt?x=14f5b19b900000
> kernel config: https://syzkaller.appspot.com/x/.config?x=20f149ad694ba4be
> dashboard link: https://syzkaller.appspot.com/bug?extid=0eac6f0bbd558fd866d7
> compiler: clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81)
> userspace arch: i386
>
> Unfortunately, I don't have any reproducer for this issue yet.
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+0eac6f0bbd558fd866d7@syzkaller.appspotmail.com
>
> =====================================================
> BUG: KMSAN: uninit-value in f2fs_lookup+0xe05/0x1a80 fs/f2fs/namei.c:503
> CPU: 0 PID: 20216 Comm: syz-executor.5 Not tainted 5.9.0-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:77 [inline]
> dump_stack+0x21c/0x280 lib/dump_stack.c:118
> kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:122
> __msan_warning+0x58/0xa0 mm/kmsan/kmsan_instr.c:219
> f2fs_lookup+0xe05/0x1a80 fs/f2fs/namei.c:503
> lookup_open fs/namei.c:3082 [inline]
> open_last_lookups fs/namei.c:3177 [inline]
> path_openat+0x2729/0x6a90 fs/namei.c:3365
> do_filp_open+0x2b8/0x710 fs/namei.c:3395
> do_sys_openat2+0xa88/0x1140 fs/open.c:1168
> do_sys_open fs/open.c:1184 [inline]
> __do_compat_sys_openat fs/open.c:1242 [inline]
> __se_compat_sys_openat+0x2a4/0x310 fs/open.c:1240
> __ia32_compat_sys_openat+0x56/0x70 fs/open.c:1240
> do_syscall_32_irqs_on arch/x86/entry/common.c:80 [inline]
> __do_fast_syscall_32+0x129/0x180 arch/x86/entry/common.c:139
> do_fast_syscall_32+0x6a/0xc0 arch/x86/entry/common.c:162
> do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:205
> entry_SYSENTER_compat_after_hwframe+0x4d/0x5c
> RIP: 0023:0xf7f73549
> Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90
> RSP: 002b:00000000f554c0cc EFLAGS: 00000296 ORIG_RAX: 0000000000000127
> RAX: ffffffffffffffda RBX: 00000000ffffff9c RCX: 0000000020000980
> RDX: 000000000002f042 RSI: 0000000000000000 RDI: 0000000000000000
> RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
> R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
>
> Local variable ----page@f2fs_lookup created at:
> f2fs_lookup+0x8f/0x1a80 fs/f2fs/namei.c:477
> f2fs_lookup+0x8f/0x1a80 fs/f2fs/namei.c:477
> =====================================================
>
>
> ---
> This report is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at syzkaller@googlegroups.com.
>
> syzbot will keep track of this issue. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
>
>
> _______________________________________________
> Linux-f2fs-devel mailing list
> Linux-f2fs-devel@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
> .
>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [f2fs-dev] KMSAN: uninit-value in f2fs_lookup
2020-09-25 9:06 ` [f2fs-dev] " Chao Yu
@ 2020-09-25 10:57 ` Dan Carpenter
2020-09-25 15:01 ` Chao Yu
2020-09-25 16:38 ` Eric Biggers
1 sibling, 1 reply; 7+ messages in thread
From: Dan Carpenter @ 2020-09-25 10:57 UTC (permalink / raw)
To: Chao Yu
Cc: syzbot, chao, glider, jaegeuk, linux-f2fs-devel, linux-kernel,
syzkaller-bugs
On Fri, Sep 25, 2020 at 05:06:33PM +0800, Chao Yu wrote:
> Hi,
>
> I don't see any problem here, thanks for your report. :)
>
I bet the uninitialize value is because "max_depth" is zero.
352 struct f2fs_dir_entry *__f2fs_find_entry(struct inode *dir,
353 const struct f2fs_filename *fname,
354 struct page **res_page)
^^^^^^^^
The stack trace says this isn't initialized.
355 {
356 unsigned long npages = dir_blocks(dir);
357 struct f2fs_dir_entry *de = NULL;
358 unsigned int max_depth;
359 unsigned int level;
360
361 if (f2fs_has_inline_dentry(dir)) {
362 *res_page = NULL;
363 de = f2fs_find_in_inline_dir(dir, fname, res_page);
364 goto out;
365 }
366
367 if (npages == 0) {
368 *res_page = NULL;
369 goto out;
370 }
371
372 max_depth = F2FS_I(dir)->i_current_depth;
373 if (unlikely(max_depth > MAX_DIR_HASH_DEPTH)) {
374 f2fs_warn(F2FS_I_SB(dir), "Corrupted max_depth of %lu: %u",
375 dir->i_ino, max_depth);
376 max_depth = MAX_DIR_HASH_DEPTH;
377 f2fs_i_depth_write(dir, max_depth);
378 }
379
380 for (level = 0; level < max_depth; level++) {
^^^^^^^^^^^^^^^^^
If "max_depth" is zero, then we never enter this loop.
381 *res_page = NULL;
382 de = find_in_level(dir, level, fname, res_page);
383 if (de || IS_ERR(*res_page))
384 break;
385 }
386 out:
387 /* This is to increase the speed of f2fs_create */
388 if (!de)
389 F2FS_I(dir)->task = current;
390 return de;
Which means that we return a NULL "de" and "*res_page" is uninitialized
and that matches what syzbot found throug runtime testing.
391 }
regards,
dan carpenter
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [f2fs-dev] KMSAN: uninit-value in f2fs_lookup
2020-09-25 10:57 ` Dan Carpenter
@ 2020-09-25 15:01 ` Chao Yu
0 siblings, 0 replies; 7+ messages in thread
From: Chao Yu @ 2020-09-25 15:01 UTC (permalink / raw)
To: Dan Carpenter, Chao Yu
Cc: syzbot, glider, jaegeuk, linux-f2fs-devel, linux-kernel, syzkaller-bugs
Hi Dan,
On 2020-9-25 18:57, Dan Carpenter wrote:
> On Fri, Sep 25, 2020 at 05:06:33PM +0800, Chao Yu wrote:
>> Hi,
>>
>> I don't see any problem here, thanks for your report. :)
>>
>
> I bet the uninitialize value is because "max_depth" is zero.
I agree with you, thanks for the hint. :)
Thanks,
>
>
> 352 struct f2fs_dir_entry *__f2fs_find_entry(struct inode *dir,
> 353 const struct f2fs_filename *fname,
> 354 struct page **res_page)
> ^^^^^^^^
> The stack trace says this isn't initialized.
>
> 355 {
> 356 unsigned long npages = dir_blocks(dir);
> 357 struct f2fs_dir_entry *de = NULL;
> 358 unsigned int max_depth;
> 359 unsigned int level;
> 360
> 361 if (f2fs_has_inline_dentry(dir)) {
> 362 *res_page = NULL;
> 363 de = f2fs_find_in_inline_dir(dir, fname, res_page);
> 364 goto out;
> 365 }
> 366
> 367 if (npages == 0) {
> 368 *res_page = NULL;
> 369 goto out;
> 370 }
> 371
> 372 max_depth = F2FS_I(dir)->i_current_depth;
> 373 if (unlikely(max_depth > MAX_DIR_HASH_DEPTH)) {
> 374 f2fs_warn(F2FS_I_SB(dir), "Corrupted max_depth of %lu: %u",
> 375 dir->i_ino, max_depth);
> 376 max_depth = MAX_DIR_HASH_DEPTH;
> 377 f2fs_i_depth_write(dir, max_depth);
> 378 }
> 379
> 380 for (level = 0; level < max_depth; level++) {
> ^^^^^^^^^^^^^^^^^
> If "max_depth" is zero, then we never enter this loop.
>
> 381 *res_page = NULL;
> 382 de = find_in_level(dir, level, fname, res_page);
> 383 if (de || IS_ERR(*res_page))
> 384 break;
> 385 }
> 386 out:
> 387 /* This is to increase the speed of f2fs_create */
> 388 if (!de)
> 389 F2FS_I(dir)->task = current;
> 390 return de;
>
> Which means that we return a NULL "de" and "*res_page" is uninitialized
> and that matches what syzbot found throug runtime testing.
>
> 391 }
>
> regards,
> dan carpenter
>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [f2fs-dev] KMSAN: uninit-value in f2fs_lookup
2020-09-25 9:06 ` [f2fs-dev] " Chao Yu
2020-09-25 10:57 ` Dan Carpenter
@ 2020-09-25 16:38 ` Eric Biggers
2020-09-25 16:45 ` Eric Biggers
1 sibling, 1 reply; 7+ messages in thread
From: Eric Biggers @ 2020-09-25 16:38 UTC (permalink / raw)
To: Chao Yu
Cc: syzbot, chao, glider, jaegeuk, linux-f2fs-devel, linux-kernel,
syzkaller-bugs
On Fri, Sep 25, 2020 at 05:06:33PM +0800, Chao Yu wrote:
> Hi,
>
> I don't see any problem here, thanks for your report. :)
>
> Thanks,
What about if max_depth == 0 in __f2fs_find_entry()? Then __f2fs_find_entry()
would return NULL without initializing *res_page.
A fix could be:
diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index 069f498af1e3..ceb4431b5669 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -357,16 +357,15 @@ struct f2fs_dir_entry *__f2fs_find_entry(struct inode *dir,
unsigned int max_depth;
unsigned int level;
+ *res_page = NULL;
+
if (f2fs_has_inline_dentry(dir)) {
- *res_page = NULL;
de = f2fs_find_in_inline_dir(dir, fname, res_page);
goto out;
}
- if (npages == 0) {
- *res_page = NULL;
+ if (npages == 0)
goto out;
- }
max_depth = F2FS_I(dir)->i_current_depth;
if (unlikely(max_depth > MAX_DIR_HASH_DEPTH)) {
@@ -377,7 +376,6 @@ struct f2fs_dir_entry *__f2fs_find_entry(struct inode *dir,
}
for (level = 0; level < max_depth; level++) {
- *res_page = NULL;
de = find_in_level(dir, level, fname, res_page);
if (de || IS_ERR(*res_page))
break;
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [f2fs-dev] KMSAN: uninit-value in f2fs_lookup
2020-09-25 16:38 ` Eric Biggers
@ 2020-09-25 16:45 ` Eric Biggers
2020-09-25 23:17 ` Chao Yu
0 siblings, 1 reply; 7+ messages in thread
From: Eric Biggers @ 2020-09-25 16:45 UTC (permalink / raw)
To: Chao Yu
Cc: syzbot, chao, glider, jaegeuk, linux-f2fs-devel, linux-kernel,
syzkaller-bugs
On Fri, Sep 25, 2020 at 09:38:19AM -0700, Eric Biggers wrote:
> On Fri, Sep 25, 2020 at 05:06:33PM +0800, Chao Yu wrote:
> > Hi,
> >
> > I don't see any problem here, thanks for your report. :)
> >
> > Thanks,
>
> What about if max_depth == 0 in __f2fs_find_entry()? Then __f2fs_find_entry()
> would return NULL without initializing *res_page.
... and I now see Dan Carpenter already pointed this out. I was a bit late!
- Eric
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [f2fs-dev] KMSAN: uninit-value in f2fs_lookup
2020-09-25 16:45 ` Eric Biggers
@ 2020-09-25 23:17 ` Chao Yu
0 siblings, 0 replies; 7+ messages in thread
From: Chao Yu @ 2020-09-25 23:17 UTC (permalink / raw)
To: Eric Biggers, Chao Yu
Cc: syzbot, glider, jaegeuk, linux-f2fs-devel, linux-kernel, syzkaller-bugs
On 2020-9-26 0:45, Eric Biggers wrote:
> On Fri, Sep 25, 2020 at 09:38:19AM -0700, Eric Biggers wrote:
>> On Fri, Sep 25, 2020 at 05:06:33PM +0800, Chao Yu wrote:
>>> Hi,
>>>
>>> I don't see any problem here, thanks for your report. :)
>>>
>>> Thanks,
>>
>> What about if max_depth == 0 in __f2fs_find_entry()? Then __f2fs_find_entry()
>> would return NULL without initializing *res_page.
>
> ... and I now see Dan Carpenter already pointed this out. I was a bit late!
Thanks for your check as well. :)
Thanks,
>
> - Eric
>
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2020-09-25 23:17 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
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2020-09-25 5:18 KMSAN: uninit-value in f2fs_lookup syzbot
2020-09-25 9:06 ` [f2fs-dev] " Chao Yu
2020-09-25 10:57 ` Dan Carpenter
2020-09-25 15:01 ` Chao Yu
2020-09-25 16:38 ` Eric Biggers
2020-09-25 16:45 ` Eric Biggers
2020-09-25 23:17 ` Chao Yu
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