[syzbot] [gfs2?] KASAN: slab-use-after-free Write in gfs2_qd_dealloc (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 18737353cca0 Merge tag 'edac_urgent_for_v6.9_rc2' of git:/..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1536130d180000
kernel config: https://syzkaller.appspot.com/x/.config?x=f64ec427e98bccd7
dashboard link: https://syzkaller.appspot.com/bug?extid=956651316bb16496a837
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1669dc5e180000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7bc7510fe41f/non_bootable_disk-18737353.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e9d064c31921/vmlinux-18737353.xz
kernel image: https://storage.googleapis.com/syzbot-assets/6d950d42963e/bzImage-18737353.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/a7a0dc360e37/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+956651...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-use-after-free in instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
BUG: KASAN: slab-use-after-free in atomic_dec_and_test include/linux/atomic/atomic-instrumented.h:1383 [inline]
BUG: KASAN: slab-use-after-free in gfs2_qd_dealloc+0x7a/0xf0 fs/gfs2/quota.c:115
Write of size 4 at addr ffff88802040ca78 by task kworker/0:1/9

CPU: 0 PID: 9 Comm: kworker/0:1 Not tainted 6.9.0-rc1-syzkaller-00379-g18737353cca0 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Workqueue: rcu_gp process_srcu
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114
print_address_description mm/kasan/report.c:377 [inline]
print_report+0xc3/0x620 mm/kasan/report.c:488
kasan_report+0xd9/0x110 mm/kasan/report.c:601
check_region_inline mm/kasan/generic.c:183 [inline]
kasan_check_range+0xef/0x1a0 mm/kasan/generic.c:189
instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
atomic_dec_and_test include/linux/atomic/atomic-instrumented.h:1383 [inline]
gfs2_qd_dealloc+0x7a/0xf0 fs/gfs2/quota.c:115
rcu_do_batch kernel/rcu/tree.c:2196 [inline]
rcu_core+0x828/0x16b0 kernel/rcu/tree.c:2471
__do_softirq+0x218/0x922 kernel/softirq.c:554
invoke_softirq kernel/softirq.c:428 [inline]
__irq_exit_rcu kernel/softirq.c:633 [inline]
irq_exit_rcu+0xb9/0x120 kernel/softirq.c:645
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
sysvec_apic_timer_interrupt+0x95/0xb0 arch/x86/kernel/apic/apic.c:1043
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:queue_delayed_work_on+0x9e/0x130 kernel/workqueue.c:2600
Code: ff 48 89 ee e8 03 e5 34 00 48 85 ed 75 46 e8 e9 e9 34 00 9c 5b 81 e3 00 02 00 00 31 ff 48 89 de e8 e7 e4 34 00 48 85 db 75 75 <e8> cd e9 34 00 44 89 e8 48 83 c4 08 5b 5d 41 5c 41 5d 41 5e 41 5f
RSP: 0018:ffffc900000c7c90 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff815888c4
RDX: ffff8880176fc880 RSI: ffffffff815888ce RDI: 0000000000000007
RBP: 0000000000000200 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000004 R12: ffff8880154b8000
R13: 0000000000000001 R14: ffff88801548a800 R15: 0000000000000000
process_one_work+0x9a9/0x1ac0 kernel/workqueue.c:3254
process_scheduled_works kernel/workqueue.c:3335 [inline]
worker_thread+0x6c8/0xf70 kernel/workqueue.c:3416
kthread+0x2c1/0x3a0 kernel/kthread.c:388
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243
</TASK>

Allocated by task 8319:
kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
kasan_save_track+0x14/0x30 mm/kasan/common.c:68
poison_kmalloc_redzone mm/kasan/common.c:370 [inline]
__kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:387
kmalloc include/linux/slab.h:628 [inline]
kzalloc include/linux/slab.h:749 [inline]
init_sbd fs/gfs2/ops_fstype.c:77 [inline]
gfs2_fill_super+0x141/0x2bf0 fs/gfs2/ops_fstype.c:1160
get_tree_bdev+0x36f/0x610 fs/super.c:1632
gfs2_get_tree+0x4e/0x280 fs/gfs2/ops_fstype.c:1341
vfs_get_tree+0x8f/0x380 fs/super.c:1797
do_new_mount fs/namespace.c:3352 [inline]
path_mount+0x14e6/0x1f20 fs/namespace.c:3679
do_mount fs/namespace.c:3692 [inline]
__do_sys_mount fs/namespace.c:3898 [inline]
__se_sys_mount fs/namespace.c:3875 [inline]
__x64_sys_mount+0x297/0x320 fs/namespace.c:3875
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xd2/0x260 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x72/0x7a

Freed by task 8319:
kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
kasan_save_track+0x14/0x30 mm/kasan/common.c:68
kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:579
poison_slab_object mm/kasan/common.c:240 [inline]
__kasan_slab_free+0x11d/0x1a0 mm/kasan/common.c:256
kasan_slab_free include/linux/kasan.h:184 [inline]
slab_free_hook mm/slub.c:2106 [inline]
slab_free mm/slub.c:4280 [inline]
kfree+0x129/0x390 mm/slub.c:4390
free_sbd fs/gfs2/ops_fstype.c:69 [inline]
gfs2_fill_super+0x13d8/0x2bf0 fs/gfs2/ops_fstype.c:1324
get_tree_bdev+0x36f/0x610 fs/super.c:1632
gfs2_get_tree+0x4e/0x280 fs/gfs2/ops_fstype.c:1341
vfs_get_tree+0x8f/0x380 fs/super.c:1797
do_new_mount fs/namespace.c:3352 [inline]
path_mount+0x14e6/0x1f20 fs/namespace.c:3679
do_mount fs/namespace.c:3692 [inline]
__do_sys_mount fs/namespace.c:3898 [inline]
__se_sys_mount fs/namespace.c:3875 [inline]
__x64_sys_mount+0x297/0x320 fs/namespace.c:3875
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xd2/0x260 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x72/0x7a

The buggy address belongs to the object at ffff88802040c000
which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 2680 bytes inside of
freed 8192-byte region [ffff88802040c000, ffff88802040e000)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x20408
head: order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff80000000840(slab|head|node=0|zone=1|lastcpupid=0xfff)
page_type: 0xffffffff()
raw: 00fff80000000840 ffff888015443180 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000020002 00000001ffffffff 0000000000000000
head: 00fff80000000840 ffff888015443180 dead000000000100 dead000000000122
head: 0000000000000000 0000000000020002 00000001ffffffff 0000000000000000
head: 00fff80000000003 ffffea0000810201 dead000000000122 00000000ffffffff
head: 0000000800000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd28c0(GFP_NOWAIT|__GFP_IO|__GFP_FS|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 4909, tgid 4909 (dhcpcd), ts 28969140910, free_ts 28042324067
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x2d4/0x350 mm/page_alloc.c:1534
prep_new_page mm/page_alloc.c:1541 [inline]
get_page_from_freelist+0xa28/0x3780 mm/page_alloc.c:3317
__alloc_pages+0x22b/0x2460 mm/page_alloc.c:4575
__alloc_pages_node include/linux/gfp.h:238 [inline]
alloc_pages_node include/linux/gfp.h:261 [inline]
alloc_slab_page mm/slub.c:2175 [inline]
allocate_slab mm/slub.c:2338 [inline]
new_slab+0xcc/0x3a0 mm/slub.c:2391
___slab_alloc+0x66d/0x1790 mm/slub.c:3525
__slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3610
__slab_alloc_node mm/slub.c:3663 [inline]
slab_alloc_node mm/slub.c:3835 [inline]
__do_kmalloc_node mm/slub.c:3965 [inline]
__kmalloc_node_track_caller+0x367/0x470 mm/slub.c:3986
kmalloc_reserve+0xef/0x2c0 net/core/skbuff.c:599
__alloc_skb+0x164/0x380 net/core/skbuff.c:668
alloc_skb include/linux/skbuff.h:1313 [inline]
netlink_dump+0x2b2/0xe00 net/netlink/af_netlink.c:2229
netlink_recvmsg+0xa13/0xf40 net/netlink/af_netlink.c:1987
sock_recvmsg_nosec net/socket.c:1046 [inline]
sock_recvmsg+0x1f6/0x250 net/socket.c:1068
____sys_recvmsg+0x21f/0x6b0 net/socket.c:2803
___sys_recvmsg+0x115/0x1a0 net/socket.c:2845
__sys_recvmsg+0x114/0x1e0 net/socket.c:2875
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xd2/0x260 arch/x86/entry/common.c:83
page last free pid 4994 tgid 4994 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1141 [inline]
free_unref_page_prepare+0x527/0xb10 mm/page_alloc.c:2347
free_unref_page+0x33/0x3c0 mm/page_alloc.c:2487
__put_partials+0x14c/0x170 mm/slub.c:2906
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x4e/0x140 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x192/0x1e0 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:322
kasan_slab_alloc include/linux/kasan.h:201 [inline]
slab_post_alloc_hook mm/slub.c:3798 [inline]
slab_alloc_node mm/slub.c:3845 [inline]
kmem_cache_alloc+0x136/0x320 mm/slub.c:3852
getname_flags.part.0+0x50/0x4f0 fs/namei.c:139
getname_flags+0x9b/0xf0 include/linux/audit.h:322
vfs_fstatat+0x9a/0x150 fs/stat.c:303
__do_sys_newfstatat+0x98/0x120 fs/stat.c:468
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xd2/0x260 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x72/0x7a

Memory state around the buggy address:
ffff88802040c900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88802040c980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88802040ca00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88802040ca80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88802040cb00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess):
0: ff 48 89 decl -0x77(%rax)
3: ee out %al,(%dx)
4: e8 03 e5 34 00 call 0x34e50c
9: 48 85 ed test %rbp,%rbp
c: 75 46 jne 0x54
e: e8 e9 e9 34 00 call 0x34e9fc
13: 9c pushf
14: 5b pop %rbx
15: 81 e3 00 02 00 00 and $0x200,%ebx
1b: 31 ff xor %edi,%edi
1d: 48 89 de mov %rbx,%rsi
20: e8 e7 e4 34 00 call 0x34e50c
25: 48 85 db test %rbx,%rbx
28: 75 75 jne 0x9f
* 2a: e8 cd e9 34 00 call 0x34e9fc <-- trapping instruction
2f: 44 89 e8 mov %r13d,%eax
32: 48 83 c4 08 add $0x8,%rsp
36: 5b pop %rbx
37: 5d pop %rbp
38: 41 5c pop %r12
3a: 41 5d pop %r13
3c: 41 5e pop %r14
3e: 41 5f pop %r15


---
This report is generated by a bot. It may contain errors.
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If the report is already addressed, let syzbot know by replying with:
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If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
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#syz undup

[Edward Adam Davis]

please test uaf in gfs2_qd_dealloc

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 18737353cca0

diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
index 572d58e86296..91103e0307ac 100644
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -1321,6 +1321,8 @@ static int gfs2_fill_super(struct super_block *sb, struct fs_context *fc)
fail_delete_wq:
destroy_workqueue(sdp->sd_delete_wq);
fail_free:
+ wait_event(sdp->sd_kill_wait,
+ atomic_read(&sdp->sd_quota_count) == 0);
free_sbd(sdp);
sb->s_fs_info = NULL;
return error;

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+956651...@syzkaller.appspotmail.com

Tested on:

commit: 18737353 Merge tag 'edac_urgent_for_v6.9_rc2' of git:/..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=16ba04c5180000

kernel config: https://syzkaller.appspot.com/x/.config?x=f64ec427e98bccd7
dashboard link: https://syzkaller.appspot.com/bug?extid=956651316bb16496a837
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=1542365e180000

Note: testing is done by a robot and is best-effort only.