* Re: [syzbot] [nilfs?] general protection fault in nilfs_clear_dirty_page
[not found] <000000000000da4f6b05eb9bf593@google.com>
@ 2023-06-11 3:56 ` syzbot
2023-06-11 21:18 ` syzbot
2023-06-12 2:14 ` [PATCH] nilfs2: prevent general protection fault in nilfs_clear_dirty_page() Ryusuke Konishi
2 siblings, 0 replies; 5+ messages in thread
From: syzbot @ 2023-06-11 3:56 UTC (permalink / raw)
To: konishi.ryusuke, linux-fsdevel, linux-kernel, linux-nilfs,
syzkaller-bugs
syzbot has found a reproducer for the following issue on:
HEAD commit: 022ce8862dff Merge tag 'i2c-for-6.4-rc6' of git://git.kern..
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=118151dd280000
kernel config: https://syzkaller.appspot.com/x/.config?x=7474de833c217bf4
dashboard link: https://syzkaller.appspot.com/bug?extid=53369d11851d8f26735c
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13e9d48b280000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12d7fa63280000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/cb6ca005422c/disk-022ce886.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/172bf908a89e/vmlinux-022ce886.xz
kernel image: https://storage.googleapis.com/syzbot-assets/4a00b7ed8430/bzImage-022ce886.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/edff56b4a75d/mount_0.gz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+53369d11851d8f26735c@syzkaller.appspotmail.com
general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 PID: 5040 Comm: syz-executor116 Not tainted 6.4.0-rc5-syzkaller-00305-g022ce8862dff #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023
RIP: 0010:nilfs_clear_dirty_page+0xa9/0x1130 fs/nilfs2/page.c:388
Code: 48 89 d8 48 c1 e8 03 42 80 3c 30 00 74 08 48 89 df e8 1b 38 97 fe 48 8b 1b 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 48 89 df e8 f9 37 97 fe 4c 8b 2b 49 8d 5d 28 48
RSP: 0018:ffffc90003d2f2e0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffea0001cb1900
RBP: ffffc90003d2f3b0 R08: ffffffff834bef29 R09: fffff94000396321
R10: 0000000000000000 R11: dffffc0000000001 R12: ffffea0001cb1900
R13: 0000000000000000 R14: dffffc0000000000 R15: dffffc0000000000
FS: 00007f996874e700(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055fe30356e00 CR3: 000000002995d000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
nilfs_clear_dirty_pages+0x1e0/0x370 fs/nilfs2/page.c:373
nilfs_writepages+0x11c/0x160 fs/nilfs2/inode.c:165
do_writepages+0x3a6/0x670 mm/page-writeback.c:2551
filemap_fdatawrite_wbc+0x125/0x180 mm/filemap.c:390
__filemap_fdatawrite_range mm/filemap.c:423 [inline]
filemap_write_and_wait_range+0x1d4/0x2c0 mm/filemap.c:678
generic_file_read_iter+0x19e/0x540 mm/filemap.c:2805
call_read_iter include/linux/fs.h:1862 [inline]
generic_file_splice_read+0x240/0x640 fs/splice.c:419
do_splice_to fs/splice.c:902 [inline]
splice_direct_to_actor+0x40c/0xbd0 fs/splice.c:973
do_splice_direct+0x283/0x3d0 fs/splice.c:1082
do_sendfile+0x620/0xff0 fs/read_write.c:1254
__do_sys_sendfile64 fs/read_write.c:1322 [inline]
__se_sys_sendfile64+0x17c/0x1e0 fs/read_write.c:1308
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f9970ac36f9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 71 15 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f996874e2f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f9970b497b0 RCX: 00007f9970ac36f9
RDX: 0000000000000000 RSI: 0000000000000008 RDI: 0000000000000007
RBP: 00007f9970b15b1c R08: 0000000000000000 R09: 0000000000000000
R10: 0001000000201005 R11: 0000000000000246 R12: 00007f9970b150c0
R13: 00000000200026c0 R14: 0032656c69662f2e R15: 00007f9970b497b8
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:nilfs_clear_dirty_page+0xa9/0x1130 fs/nilfs2/page.c:388
Code: 48 89 d8 48 c1 e8 03 42 80 3c 30 00 74 08 48 89 df e8 1b 38 97 fe 48 8b 1b 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 08 48 89 df e8 f9 37 97 fe 4c 8b 2b 49 8d 5d 28 48
RSP: 0018:ffffc90003d2f2e0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffea0001cb1900
RBP: ffffc90003d2f3b0 R08: ffffffff834bef29 R09: fffff94000396321
R10: 0000000000000000 R11: dffffc0000000001 R12: ffffea0001cb1900
R13: 0000000000000000 R14: dffffc0000000000 R15: dffffc0000000000
FS: 00007f996874e700(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9970b1500a CR3: 000000002995d000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 48 89 d8 mov %rbx,%rax
3: 48 c1 e8 03 shr $0x3,%rax
7: 42 80 3c 30 00 cmpb $0x0,(%rax,%r14,1)
c: 74 08 je 0x16
e: 48 89 df mov %rbx,%rdi
11: e8 1b 38 97 fe callq 0xfe973831
16: 48 8b 1b mov (%rbx),%rbx
19: 48 89 d8 mov %rbx,%rax
1c: 48 c1 e8 03 shr $0x3,%rax
20: 48 b9 00 00 00 00 00 movabs $0xdffffc0000000000,%rcx
27: fc ff df
* 2a: 80 3c 08 00 cmpb $0x0,(%rax,%rcx,1) <-- trapping instruction
2e: 74 08 je 0x38
30: 48 89 df mov %rbx,%rdi
33: e8 f9 37 97 fe callq 0xfe973831
38: 4c 8b 2b mov (%rbx),%r13
3b: 49 8d 5d 28 lea 0x28(%r13),%rbx
3f: 48 rex.W
---
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.
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [syzbot] [nilfs?] general protection fault in nilfs_clear_dirty_page
[not found] <000000000000da4f6b05eb9bf593@google.com>
2023-06-11 3:56 ` [syzbot] [nilfs?] general protection fault in nilfs_clear_dirty_page syzbot
@ 2023-06-11 21:18 ` syzbot
2023-06-12 3:30 ` Christoph Hellwig
2023-06-12 2:14 ` [PATCH] nilfs2: prevent general protection fault in nilfs_clear_dirty_page() Ryusuke Konishi
2 siblings, 1 reply; 5+ messages in thread
From: syzbot @ 2023-06-11 21:18 UTC (permalink / raw)
To: axboe, dsterba, hch, konishi.ryusuke, linux-block, linux-fsdevel,
linux-kernel, linux-nilfs, syzkaller-bugs, wqu
syzbot has bisected this issue to:
commit 4a445b7b6178d88956192c0202463063f52e8667
Author: Qu Wenruo <wqu@suse.com>
Date: Sat Aug 13 08:06:53 2022 +0000
btrfs: don't merge pages into bio if their page offset is not contiguous
bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=17778475280000
start commit: 022ce8862dff Merge tag 'i2c-for-6.4-rc6' of git://git.kern..
git tree: upstream
final oops: https://syzkaller.appspot.com/x/report.txt?x=14f78475280000
console output: https://syzkaller.appspot.com/x/log.txt?x=10f78475280000
kernel config: https://syzkaller.appspot.com/x/.config?x=7474de833c217bf4
dashboard link: https://syzkaller.appspot.com/bug?extid=53369d11851d8f26735c
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13e9d48b280000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12d7fa63280000
Reported-by: syzbot+53369d11851d8f26735c@syzkaller.appspotmail.com
Fixes: 4a445b7b6178 ("btrfs: don't merge pages into bio if their page offset is not contiguous")
For information about bisection process see: https://goo.gl/tpsmEJ#bisection
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [syzbot] [nilfs?] general protection fault in nilfs_clear_dirty_page
2023-06-11 21:18 ` syzbot
@ 2023-06-12 3:30 ` Christoph Hellwig
2023-06-12 3:59 ` Ryusuke Konishi
0 siblings, 1 reply; 5+ messages in thread
From: Christoph Hellwig @ 2023-06-12 3:30 UTC (permalink / raw)
To: syzbot
Cc: axboe, dsterba, hch, konishi.ryusuke, linux-block, linux-fsdevel,
linux-kernel, linux-nilfs, syzkaller-bugs, wqu
On Sun, Jun 11, 2023 at 02:18:29PM -0700, syzbot wrote:
> syzbot has bisected this issue to:
>
> commit 4a445b7b6178d88956192c0202463063f52e8667
> Author: Qu Wenruo <wqu@suse.com>
> Date: Sat Aug 13 08:06:53 2022 +0000
>
> btrfs: don't merge pages into bio if their page offset is not contiguous
I can't see how that btrfs commit would affect nilfs2..
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [syzbot] [nilfs?] general protection fault in nilfs_clear_dirty_page
2023-06-12 3:30 ` Christoph Hellwig
@ 2023-06-12 3:59 ` Ryusuke Konishi
0 siblings, 0 replies; 5+ messages in thread
From: Ryusuke Konishi @ 2023-06-12 3:59 UTC (permalink / raw)
To: Christoph Hellwig
Cc: syzbot, axboe, dsterba, linux-block, linux-fsdevel, linux-kernel,
linux-nilfs, syzkaller-bugs, wqu
On Mon, Jun 12, 2023 at 12:30 PM Christoph Hellwig wrote:
>
> On Sun, Jun 11, 2023 at 02:18:29PM -0700, syzbot wrote:
> > syzbot has bisected this issue to:
> >
> > commit 4a445b7b6178d88956192c0202463063f52e8667
> > Author: Qu Wenruo <wqu@suse.com>
> > Date: Sat Aug 13 08:06:53 2022 +0000
> >
> > btrfs: don't merge pages into bio if their page offset is not contiguous
>
> I can't see how that btrfs commit would affect nilfs2..
Yeah, I think this bisection result is wrong.
I have already posted a bug-fix patch titled "nilfs2: prevent general
protection fault in nilfs_clear_dirty_page()"
for this issue.
Thanks,
Ryusuke Konishi
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH] nilfs2: prevent general protection fault in nilfs_clear_dirty_page()
[not found] <000000000000da4f6b05eb9bf593@google.com>
2023-06-11 3:56 ` [syzbot] [nilfs?] general protection fault in nilfs_clear_dirty_page syzbot
2023-06-11 21:18 ` syzbot
@ 2023-06-12 2:14 ` Ryusuke Konishi
2 siblings, 0 replies; 5+ messages in thread
From: Ryusuke Konishi @ 2023-06-12 2:14 UTC (permalink / raw)
To: Andrew Morton
Cc: linux-nilfs, syzbot, syzkaller-bugs, linux-kernel, linux-fsdevel
In a syzbot stress test that deliberately causes file system errors on
nilfs2 with a corrupted disk image, it has been reported that
nilfs_clear_dirty_page() called from nilfs_clear_dirty_pages() can cause
a general protection fault.
In nilfs_clear_dirty_pages(), when looking up dirty pages from the page
cache and calling nilfs_clear_dirty_page() for each dirty page/folio
retrieved, the back reference from the argument page to "mapping" may have
been changed to NULL (and possibly others). It is necessary to check
this after locking the page/folio.
So, fix this issue by not calling nilfs_clear_dirty_page() on a page/folio
after locking it in nilfs_clear_dirty_pages() if the back reference
"mapping" from the page/folio is different from the "mapping" that held
the page/folio just before.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Reported-by: syzbot+53369d11851d8f26735c@syzkaller.appspotmail.com
Closes: https://lkml.kernel.org/r/000000000000da4f6b05eb9bf593@google.com
Tested-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: stable@vger.kernel.org
---
fs/nilfs2/page.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/fs/nilfs2/page.c b/fs/nilfs2/page.c
index 5cf30827f244..b4e54d079b7d 100644
--- a/fs/nilfs2/page.c
+++ b/fs/nilfs2/page.c
@@ -370,7 +370,15 @@ void nilfs_clear_dirty_pages(struct address_space *mapping, bool silent)
struct folio *folio = fbatch.folios[i];
folio_lock(folio);
- nilfs_clear_dirty_page(&folio->page, silent);
+
+ /*
+ * This folio may have been removed from the address
+ * space by truncation or invalidation when the lock
+ * was acquired. Skip processing in that case.
+ */
+ if (likely(folio->mapping == mapping))
+ nilfs_clear_dirty_page(&folio->page, silent);
+
folio_unlock(folio);
}
folio_batch_release(&fbatch);
--
2.34.1
^ permalink raw reply related [flat|nested] 5+ messages in thread