* [syzbot] [ocfs2?] general protection fault in ocfs2_xa_block_wipe_namevalue
@ 2024-10-27 10:19 syzbot
2024-10-29 21:40 ` [syzbot] check ocfs2_xa_remove fix, please syzbot
2024-11-03 18:40 ` [syzbot] check ocfs2_xa_remove fix [v2] syzbot
0 siblings, 2 replies; 6+ messages in thread
From: syzbot @ 2024-10-27 10:19 UTC (permalink / raw)
To: jlbec, joseph.qi, linux-kernel, mark, ocfs2-devel, syzkaller-bugs
Hello,
syzbot found the following issue on:
HEAD commit: c2ee9f594da8 KVM: selftests: Fix build on on non-x86 archi..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12d688a7980000
kernel config: https://syzkaller.appspot.com/x/.config?x=fc6f8ce8c5369043
dashboard link: https://syzkaller.appspot.com/bug?extid=386ce9e60fa1b18aac5b
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=11ff2a5f980000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=131c4c30580000
Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-c2ee9f59.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/8a3541902b13/vmlinux-c2ee9f59.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a00efacc2604/bzImage-c2ee9f59.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/24458d1e01ba/mount_0.gz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+386ce9e60fa1b18aac5b@syzkaller.appspotmail.com
(syz-executor887,5095,0):ocfs2_xa_remove:2028 ERROR: status = -12
(syz-executor887,5095,0):ocfs2_xa_cleanup_value_truncate:1999 ERROR: Partial truncate while removing xattr overlay.upper. Leaking 1 clusters and removing the entry
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 UID: 0 PID: 5095 Comm: syz-executor887 Not tainted 6.12.0-rc4-syzkaller-00047-gc2ee9f594da8 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:ocfs2_xa_block_wipe_namevalue+0x91/0x550 fs/ocfs2/xattr.c:1637
Code: f8 48 c1 e8 03 48 bb 00 00 00 00 00 fc ff df 0f b6 04 18 84 c0 0f 85 f7 03 00 00 45 0f b7 27 49 8d 7d 04 48 89 f8 48 c1 e8 03 <0f> b6 04 18 84 c0 0f 85 f9 03 00 00 41 0f b7 45 04 89 44 24 04 49
RSP: 0018:ffffc9000aecebf0 EFLAGS: 00010247
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 00000000fffffff4 RDI: 0000000000000004
RBP: ffffc9000aecf418 R08: ffffffff83a08052 R09: 0000000000000000
R10: ffff8880473f73c0 R11: ffffffff83a0a5e0 R12: 0000000000000000
R13: 0000000000000000 R14: ffffc9000aecf410 R15: ffff8880473f7230
FS: 000055557176f380(0000) GS:ffff88801fc00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020001400 CR3: 000000003fa50000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
ocfs2_xa_wipe_namevalue fs/ocfs2/xattr.c:1470 [inline]
ocfs2_xa_remove_entry fs/ocfs2/xattr.c:1941 [inline]
ocfs2_xa_remove fs/ocfs2/xattr.c:2044 [inline]
ocfs2_xa_set+0x1120/0x2b40 fs/ocfs2/xattr.c:2248
ocfs2_xattr_block_set+0x46e/0x3390 fs/ocfs2/xattr.c:2986
__ocfs2_xattr_set_handle+0x28c/0x10a0
ocfs2_xattr_set+0x128c/0x1930 fs/ocfs2/xattr.c:3651
__vfs_removexattr+0x42a/0x460 fs/xattr.c:518
__vfs_removexattr_locked+0x206/0x450 fs/xattr.c:553
vfs_removexattr+0x103/0x2b0 fs/xattr.c:575
removexattr fs/xattr.c:907 [inline]
path_removexattr+0x284/0x3a0 fs/xattr.c:928
__do_sys_lremovexattr fs/xattr.c:948 [inline]
__se_sys_lremovexattr fs/xattr.c:945 [inline]
__x64_sys_lremovexattr+0x5d/0x70 fs/xattr.c:945
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fdd4bc7a7c9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 d1 1a 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:00007fffe80c9a48 EFLAGS: 00000246 ORIG_RAX: 00000000000000c6
RAX: ffffffffffffffda RBX: 00007fffe80c9a60 RCX: 00007fdd4bc7a7c9
RDX: 00007fdd4bc79950 RSI: 0000000020000280 RDI: 0000000020000240
RBP: 0000000000000001 R08: 00007fffe80c97e7 R09: 0000555571770378
R10: 0000000000000001 R11: 0000000000000246 R12: 00007fffe80c9a80
R13: 00007fffe80c9ca8 R14: 431bde82d7b634db R15: 00007fdd4bcbc01d
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:ocfs2_xa_block_wipe_namevalue+0x91/0x550 fs/ocfs2/xattr.c:1637
Code: f8 48 c1 e8 03 48 bb 00 00 00 00 00 fc ff df 0f b6 04 18 84 c0 0f 85 f7 03 00 00 45 0f b7 27 49 8d 7d 04 48 89 f8 48 c1 e8 03 <0f> b6 04 18 84 c0 0f 85 f9 03 00 00 41 0f b7 45 04 89 44 24 04 49
RSP: 0018:ffffc9000aecebf0 EFLAGS: 00010247
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 00000000fffffff4 RDI: 0000000000000004
RBP: ffffc9000aecf418 R08: ffffffff83a08052 R09: 0000000000000000
R10: ffff8880473f73c0 R11: ffffffff83a0a5e0 R12: 0000000000000000
R13: 0000000000000000 R14: ffffc9000aecf410 R15: ffff8880473f7230
FS: 000055557176f380(0000) GS:ffff88801fc00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020001400 CR3: 000000003fa50000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: f8 clc
1: 48 c1 e8 03 shr $0x3,%rax
5: 48 bb 00 00 00 00 00 movabs $0xdffffc0000000000,%rbx
c: fc ff df
f: 0f b6 04 18 movzbl (%rax,%rbx,1),%eax
13: 84 c0 test %al,%al
15: 0f 85 f7 03 00 00 jne 0x412
1b: 45 0f b7 27 movzwl (%r15),%r12d
1f: 49 8d 7d 04 lea 0x4(%r13),%rdi
23: 48 89 f8 mov %rdi,%rax
26: 48 c1 e8 03 shr $0x3,%rax
* 2a: 0f b6 04 18 movzbl (%rax,%rbx,1),%eax <-- trapping instruction
2e: 84 c0 test %al,%al
30: 0f 85 f9 03 00 00 jne 0x42f
36: 41 0f b7 45 04 movzwl 0x4(%r13),%eax
3b: 89 44 24 04 mov %eax,0x4(%rsp)
3f: 49 rex.WB
---
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^ permalink raw reply [flat|nested] 6+ messages in thread
[parent not found: <67215651.a70a0220.31b018.c8d7@mx.google.com>]
* Re: [syzbot] [ocfs2?] general protection fault in [v2] ocfs2_xa_block_wipe_namevalue
2024-10-29 22:00 ` [syzbot] [ocfs2?] general protection fault in ocfs2_xa_block_wipe_namevalue syzbot
@ 2024-11-02 16:37 Andrew Kanner
2024-11-03 19:05 ` [syzbot] [ocfs2?] general protection fault in ocfs2_xa_block_wipe_namevalue syzbot
-1 siblings, 1 reply; 6+ messages in thread
From: Andrew Kanner @ 2024-11-02 16:37 UTC (permalink / raw)
To: syzbot; +Cc: linux-kernel, syzkaller-bugs
[-- Attachment #1: Type: text/plain, Size: 82 bytes --]
#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
[-- Attachment #2: v2-0001-ocfs2-remove-entry-once-instead-of-null-ptr-derefere.patch --]
[-- Type: text/plain, Size: 3537 bytes --]
From 8a9998952cc5d493cbb6ae9e6187347787b88694 Mon Sep 17 00:00:00 2001
From: Andrew Kanner <andrew.kanner@gmail.com>
Date: Tue, 29 Oct 2024 21:26:30 +0100
Subject: [PATCH] ocfs2: remove entry once instead of null-ptr-dereference in
ocfs2_xa_remove()
Syzkaller is able to provoke null-ptr-dereference in ocfs2_xa_remove():
[ 57.319872] (a.out,1161,7):ocfs2_xa_remove:2028 ERROR: status = -12
[ 57.320420] (a.out,1161,7):ocfs2_xa_cleanup_value_truncate:1999 ERROR: Partial truncate while removing xattr overlay.upper. Leaking 1 clusters and removing the entry
[ 57.321727] BUG: kernel NULL pointer dereference, address: 0000000000000004
[...]
[ 57.325727] RIP: 0010:ocfs2_xa_block_wipe_namevalue+0x2a/0xc0
[...]
[ 57.331328] Call Trace:
[ 57.331477] <TASK>
[...]
[ 57.333511] ? do_user_addr_fault+0x3e5/0x740
[ 57.333778] ? exc_page_fault+0x70/0x170
[ 57.334016] ? asm_exc_page_fault+0x2b/0x30
[ 57.334263] ? __pfx_ocfs2_xa_block_wipe_namevalue+0x10/0x10
[ 57.334596] ? ocfs2_xa_block_wipe_namevalue+0x2a/0xc0
[ 57.334913] ocfs2_xa_remove_entry+0x23/0xc0
[ 57.335164] ocfs2_xa_set+0x704/0xcf0
[ 57.335381] ? _raw_spin_unlock+0x1a/0x40
[ 57.335620] ? ocfs2_inode_cache_unlock+0x16/0x20
[ 57.335915] ? trace_preempt_on+0x1e/0x70
[ 57.336153] ? start_this_handle+0x16c/0x500
[ 57.336410] ? preempt_count_sub+0x50/0x80
[ 57.336656] ? _raw_read_unlock+0x20/0x40
[ 57.336906] ? start_this_handle+0x16c/0x500
[ 57.337162] ocfs2_xattr_block_set+0xa6/0x1e0
[ 57.337424] __ocfs2_xattr_set_handle+0x1fd/0x5d0
[ 57.337706] ? ocfs2_start_trans+0x13d/0x290
[ 57.337971] ocfs2_xattr_set+0xb13/0xfb0
[ 57.338207] ? dput+0x46/0x1c0
[ 57.338393] ocfs2_xattr_trusted_set+0x28/0x30
[ 57.338665] ? ocfs2_xattr_trusted_set+0x28/0x30
[ 57.338948] __vfs_removexattr+0x92/0xc0
[ 57.339182] __vfs_removexattr_locked+0xd5/0x190
[ 57.339456] ? preempt_count_sub+0x50/0x80
[ 57.339705] vfs_removexattr+0x5f/0x100
[...]
Reproducer uses faultinject facility to fail ocfs2_xa_remove() ->
ocfs2_xa_value_truncate() with -ENOMEM.
In this case the comment mentions that we can return 0 if
ocfs2_xa_cleanup_value_truncate() is going to wipe the entry
anyway. But the following 'rc' check is wrong and execution flow do
'ocfs2_xa_remove_entry(loc);' twice:
* 1st: in ocfs2_xa_cleanup_value_truncate();
* 2nd: returning back to ocfs2_xa_remove() instead of going to 'out'.
Fix this by skipping the 2nd removal of the same entry and making
syzkaller repro happy.
Cc: stable@vger.kernel.org
Fixes: 399ff3a748cf ("ocfs2: Handle errors while setting external xattr values.")
Reported-by: syzbot+386ce9e60fa1b18aac5b@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/671e13ab.050a0220.2b8c0f.01d0.GAE@google.com/T/
Tested-by: syzbot+386ce9e60fa1b18aac5b@syzkaller.appspotmail.com
Signed-off-by: Andrew Kanner <andrew.kanner@gmail.com>
---
Notes (akanner):
v2: remove rc check completely, suggested by Joseph Qi <joseph.qi@linux.alibaba.com>
v1: https://lore.kernel.org/all/20241029224304.2169092-2-andrew.kanner@gmail.com/T/
fs/ocfs2/xattr.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c
index dd0a05365e79..73a6f6fd8a8e 100644
--- a/fs/ocfs2/xattr.c
+++ b/fs/ocfs2/xattr.c
@@ -2036,8 +2036,7 @@ static int ocfs2_xa_remove(struct ocfs2_xa_loc *loc,
rc = 0;
ocfs2_xa_cleanup_value_truncate(loc, "removing",
orig_clusters);
- if (rc)
- goto out;
+ goto out;
}
}
--
2.43.5
^ permalink raw reply related [flat|nested] 6+ messages in thread[parent not found: <6727c3ac.170a0220.27f534.dc51@mx.google.com>]
end of thread, other threads:[~2024-11-03 19:25 UTC | newest]
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2024-10-27 10:19 [syzbot] [ocfs2?] general protection fault in ocfs2_xa_block_wipe_namevalue syzbot
2024-10-29 21:40 ` [syzbot] check ocfs2_xa_remove fix, please syzbot
2024-11-03 18:40 ` [syzbot] check ocfs2_xa_remove fix [v2] syzbot
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2024-10-29 22:00 ` [syzbot] [ocfs2?] general protection fault in ocfs2_xa_block_wipe_namevalue syzbot
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2024-11-02 16:37 [syzbot] [ocfs2?] general protection fault in [v2] ocfs2_xa_block_wipe_namevalue Andrew Kanner
2024-11-03 19:05 ` [syzbot] [ocfs2?] general protection fault in ocfs2_xa_block_wipe_namevalue syzbot
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