[syzbot] [f2fs?] WARNING: lock held when returning to user space in f2fs_ioc_start_atomic_write

[syzbot] [f2fs?] WARNING: lock held when returning to user space in f2fs_ioc_start_atomic_write

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    9e6869691724 Add linux-next specific files for 20240812
git tree:       linux-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=1431e405980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=61ba6f3b22ee5467
dashboard link: https://syzkaller.appspot.com/bug?extid=733300ca0a9baca7e245
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=120ed77d980000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=130e0ef3980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/f1b086192f50/disk-9e686969.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/b457920fb52e/vmlinux-9e686969.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e63ba9cce98a/bzImage-9e686969.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/08b48c782593/mount_0.gz

The issue was bisected to:

commit 374a8881ce4ccf787f5381a39f825cb17a3f6b14
Author: Chao Yu <chao@kernel.org>
Date:   Tue Jun 25 03:13:51 2024 +0000

    f2fs: atomic: fix to forbid dio in atomic_file

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=10741429980000
final oops:     https://syzkaller.appspot.com/x/report.txt?x=12741429980000
console output: https://syzkaller.appspot.com/x/log.txt?x=14741429980000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+733300ca0a9baca7e245@syzkaller.appspotmail.com
Fixes: 374a8881ce4c ("f2fs: atomic: fix to forbid dio in atomic_file")

F2FS-fs (loop0): Found nat_bits in checkpoint
F2FS-fs (loop0): Mounted with checkpoint version = 48b305e5
syz-executor312: attempt to access beyond end of device
loop0: rw=10241, sector=45096, nr_sectors = 8 limit=40427
================================================
WARNING: lock held when returning to user space!
6.11.0-rc3-next-20240812-syzkaller #0 Not tainted
------------------------------------------------
syz-executor312/5227 is leaving the kernel with locks still held!
1 lock held by syz-executor312/5227:
 #0: ffff8880695aa0e0 (&fi->i_gc_rwsem[READ]){+.+.}-{3:3}, at: f2fs_down_write fs/f2fs/f2fs.h:2196 [inline]
 #0: ffff8880695aa0e0 (&fi->i_gc_rwsem[READ]){+.+.}-{3:3}, at: f2fs_ioc_start_atomic_write+0x2ed/0xac0 fs/f2fs/file.c:2163


---
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.
For information about bisection process see: https://goo.gl/tpsmEJ#bisection

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

Re: [syzbot] [f2fs?] WARNING: lock held when returning to user space in f2fs_commit_atomic_write

[Edward Adam Davis]

unlock i_gc_rwsem[WRITE] before quiting f2fs_commit_atomic_write

Fixes: 7566a155c666 ("f2fs: atomic: fix to not allow GC to pollute atomic_file")
Reported-by: syzbot+78ff2855f26377625419@syzkaller.appspotmail.com

correct git tree to linux-next

#syz test: linux-next 9e6869691724

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 741e46f9d0fd..a43054ab0cf1 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -389,13 +389,13 @@ int f2fs_commit_atomic_write(struct inode *inode)
 
 	err = filemap_write_and_wait_range(inode->i_mapping, 0, LLONG_MAX);
 	if (err)
-		return err;
+		goto out;
 
 	/* writeback GCing page of cow_inode */
 	err = filemap_write_and_wait_range(fi->cow_inode->i_mapping,
 							0, LLONG_MAX);
 	if (err)
-		return err;
+		goto out;
 
 	filemap_invalidate_lock(inode->i_mapping);
 
@@ -407,6 +407,7 @@ int f2fs_commit_atomic_write(struct inode *inode)
 	f2fs_unlock_op(sbi);
 
 	filemap_invalidate_unlock(inode->i_mapping);
+out:
 	f2fs_up_write(&fi->i_gc_rwsem[WRITE]);
 
 	return err;

Re: [syzbot] WARNING: lock held when returning to user space in f2fs_ioc_start_atomic_write

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org.

***

Subject: WARNING: lock held when returning to user space in f2fs_ioc_start_atomic_write
Author: djahchankoike@gmail.com

#syz test

Reader lock unreleased when returning upon error.

Signed-off-by: Diogo Jahchan Koike <djahchankoike@gmail.com>
---
 fs/f2fs/file.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 270c32e3385f..3ce8478ae5be 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -2172,6 +2172,7 @@ static int f2fs_ioc_start_atomic_write(struct file *filp, bool truncate)
 	ret = filemap_write_and_wait_range(inode->i_mapping, 0, LLONG_MAX);
 	if (ret) {
 		f2fs_up_write(&fi->i_gc_rwsem[WRITE]);
+		f2fs_up_write(&fi->i_gc_rwsem[READ]);
 		goto out;
 	}
 
@@ -2181,6 +2182,7 @@ static int f2fs_ioc_start_atomic_write(struct file *filp, bool truncate)
 		pinode = f2fs_iget(inode->i_sb, fi->i_pino);
 		if (IS_ERR(pinode)) {
 			f2fs_up_write(&fi->i_gc_rwsem[WRITE]);
+			f2fs_up_write(&fi->i_gc_rwsem[READ]);
 			ret = PTR_ERR(pinode);
 			goto out;
 		}
@@ -2189,6 +2191,7 @@ static int f2fs_ioc_start_atomic_write(struct file *filp, bool truncate)
 		iput(pinode);
 		if (ret) {
 			f2fs_up_write(&fi->i_gc_rwsem[WRITE]);
+			f2fs_up_write(&fi->i_gc_rwsem[READ]);
 			goto out;
 		}
 
@@ -2202,6 +2205,7 @@ static int f2fs_ioc_start_atomic_write(struct file *filp, bool truncate)
 		ret = f2fs_do_truncate_blocks(fi->cow_inode, 0, true);
 		if (ret) {
 			f2fs_up_write(&fi->i_gc_rwsem[WRITE]);
+			f2fs_up_write(&fi->i_gc_rwsem[READ]);
 			goto out;
 		}
 	}
-- 
2.39.2

Re: [syzbot] [f2fs?] WARNING: lock held when returning to user space in f2fs_ioc_start_atomic_write

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
WARNING: lock held when returning to user space in f2fs_ioc_start_atomic_write

F2FS-fs (loop0): Mounted with checkpoint version = 48b305e5
syz.0.15: attempt to access beyond end of device
loop0: rw=10241, sector=45096, nr_sectors = 8 limit=40427
================================================
WARNING: lock held when returning to user space!
6.11.0-rc3-next-20240812-syzkaller-dirty #0 Not tainted
------------------------------------------------
syz.0.15/6178 is leaving the kernel with locks still held!
1 lock held by syz.0.15/6178:
 #0: ffff88807032a0e0 (&fi->i_gc_rwsem[READ]){+.+.}-{3:3}, at: f2fs_down_write fs/f2fs/f2fs.h:2196 [inline]
 #0: ffff88807032a0e0 (&fi->i_gc_rwsem[READ]){+.+.}-{3:3}, at: f2fs_ioc_start_atomic_write+0x2ed/0xac0 fs/f2fs/file.c:2163


Tested on:

commit:         9e686969 Add linux-next specific files for 20240812
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
console output: https://syzkaller.appspot.com/x/log.txt?x=16367cfd980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=61ba6f3b22ee5467
dashboard link: https://syzkaller.appspot.com/bug?extid=733300ca0a9baca7e245
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1510e1f5980000

Re: [syzbot] [f2fs?] WARNING: lock held when returning to user space in f2fs_ioc_start_atomic_write

[Chao Yu]

#syz fix: f2fs: atomic: fix to forbid dio in atomic_file

On 2024/8/14 19:51, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    9e6869691724 Add linux-next specific files for 20240812
> git tree:       linux-next
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=1431e405980000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=61ba6f3b22ee5467
> dashboard link: https://syzkaller.appspot.com/bug?extid=733300ca0a9baca7e245
> compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=120ed77d980000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=130e0ef3980000
> 
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/f1b086192f50/disk-9e686969.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/b457920fb52e/vmlinux-9e686969.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/e63ba9cce98a/bzImage-9e686969.xz
> mounted in repro: https://storage.googleapis.com/syzbot-assets/08b48c782593/mount_0.gz
> 
> The issue was bisected to:
> 
> commit 374a8881ce4ccf787f5381a39f825cb17a3f6b14
> Author: Chao Yu <chao@kernel.org>
> Date:   Tue Jun 25 03:13:51 2024 +0000
> 
>      f2fs: atomic: fix to forbid dio in atomic_file
> 
> bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=10741429980000
> final oops:     https://syzkaller.appspot.com/x/report.txt?x=12741429980000
> console output: https://syzkaller.appspot.com/x/log.txt?x=14741429980000
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+733300ca0a9baca7e245@syzkaller.appspotmail.com
> Fixes: 374a8881ce4c ("f2fs: atomic: fix to forbid dio in atomic_file")
> 
> F2FS-fs (loop0): Found nat_bits in checkpoint
> F2FS-fs (loop0): Mounted with checkpoint version = 48b305e5
> syz-executor312: attempt to access beyond end of device
> loop0: rw=10241, sector=45096, nr_sectors = 8 limit=40427
> ================================================
> WARNING: lock held when returning to user space!
> 6.11.0-rc3-next-20240812-syzkaller #0 Not tainted
> ------------------------------------------------
> syz-executor312/5227 is leaving the kernel with locks still held!
> 1 lock held by syz-executor312/5227:
>   #0: ffff8880695aa0e0 (&fi->i_gc_rwsem[READ]){+.+.}-{3:3}, at: f2fs_down_write fs/f2fs/f2fs.h:2196 [inline]
>   #0: ffff8880695aa0e0 (&fi->i_gc_rwsem[READ]){+.+.}-{3:3}, at: f2fs_ioc_start_atomic_write+0x2ed/0xac0 fs/f2fs/file.c:2163
> 
> 
> ---
> 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.
> For information about bisection process see: https://goo.gl/tpsmEJ#bisection
> 
> If the report is already addressed, let syzbot know by replying with:
> #syz fix: exact-commit-title
> 
> If you want syzbot to run the reproducer, reply with:
> #syz test: git://repo/address.git branch-or-commit-hash
> If you attach or paste a git patch, syzbot will apply it before testing.
> 
> If you want to overwrite report's subsystems, reply with:
> #syz set subsystems: new-subsystem
> (See the list of subsystem names on the web dashboard)
> 
> If the report is a duplicate of another one, reply with:
> #syz dup: exact-subject-of-another-report
> 
> If you want to undo deduplication, reply with:
> #syz undup