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KASAN: use-after-free Read in btrfs_mount (2)

Status: upstream: reported C repro on 2020/06/23 11:09
Reported-by: syzbot+ff363b420c81ba0b624c@syzkaller.appspotmail.com
First crash: 1614d, last: 1078d
Fix bisection: failed (error log, bisect log)
  
▶ ▼ Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.14 KASAN: use-after-free Read in btrfs_mount 1 1870d 1870d 0/1 auto-closed as invalid on 2020/02/08 08:17
▶ ▼ Last patch testing requests (2)
Created Duration User Patch Repo Result
2023/02/08 20:32 13m retest repro linux-4.14.y report log
2022/09/18 12:29 10m retest repro linux-4.14.y report log
▶ ▼ Fix bisection attempts (2)
Created Duration User Patch Repo Result
2020/09/07 17:03 16m bisect fix linux-4.14.y error job log
2020/08/08 01:07 25m bisect fix linux-4.14.y OK (0) job log log

Sample crash report:
RBP: 0000000000000000 R08: 00007fff34f94060 R09: 0000000000000000
R10: 0000000000000005 R11: 0000000000000293 R12: 0000000000000001
R13: 0000000000403100 R14: 0000000000000000 R15: 0000000000000000
==================================================================
BUG: KASAN: use-after-free in free_fs_info fs/btrfs/ctree.h:2931 [inline]
BUG: KASAN: use-after-free in btrfs_mount+0x2412/0x2838 fs/btrfs/super.c:1644
Read of size 8 at addr ffff8880a3c42258 by task syz-executor309/6783

CPU: 0 PID: 6783 Comm: syz-executor309 Not tainted 4.14.184-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x1b2/0x283 lib/dump_stack.c:58
 print_address_description.cold+0x54/0x1dc mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report mm/kasan/report.c:409 [inline]
 kasan_report.cold+0xa9/0x2b9 mm/kasan/report.c:393
 free_fs_info fs/btrfs/ctree.h:2931 [inline]
 btrfs_mount+0x2412/0x2838 fs/btrfs/super.c:1644
 mount_fs+0x92/0x2a0 fs/super.c:1237
 vfs_kern_mount.part.0+0x5b/0x3c0 fs/namespace.c:1046
 vfs_kern_mount+0x3c/0x60 fs/namespace.c:1036
 mount_subvol fs/btrfs/super.c:1392 [inline]
 btrfs_mount+0x2a0/0x2838 fs/btrfs/super.c:1563
 mount_fs+0x92/0x2a0 fs/super.c:1237
 vfs_kern_mount.part.0+0x5b/0x3c0 fs/namespace.c:1046
 vfs_kern_mount fs/namespace.c:1036 [inline]
 do_new_mount fs/namespace.c:2549 [inline]
 do_mount+0x3c9/0x25e0 fs/namespace.c:2879
 SYSC_mount fs/namespace.c:3095 [inline]
 SyS_mount+0xa8/0x120 fs/namespace.c:3072
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x44898a
RSP: 002b:00007fff34f93fb8 EFLAGS: 00000293 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000044898a
RDX: 00007fff34f94000 RSI: 00000000200001c0 RDI: 00007fff34f94020
RBP: 0000000000000000 R08: 00007fff34f94060 R09: 0000000000000000
R10: 0000000000000005 R11: 0000000000000293 R12: 0000000000000008
R13: 0000000000403100 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 6783:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc.part.0+0x4f/0xd0 mm/kasan/kasan.c:551
 __do_kmalloc_node mm/slab.c:3682 [inline]
 __kmalloc_node+0x4c/0x70 mm/slab.c:3689
 kmalloc_node include/linux/slab.h:530 [inline]
 kvmalloc_node+0x88/0xd0 mm/util.c:397
 kvmalloc include/linux/mm.h:531 [inline]
 kvzalloc include/linux/mm.h:539 [inline]
 btrfs_mount+0xea4/0x2838 fs/btrfs/super.c:1584
 mount_fs+0x92/0x2a0 fs/super.c:1237
 vfs_kern_mount.part.0+0x5b/0x3c0 fs/namespace.c:1046
 vfs_kern_mount+0x3c/0x60 fs/namespace.c:1036
 mount_subvol fs/btrfs/super.c:1392 [inline]
 btrfs_mount+0x2a0/0x2838 fs/btrfs/super.c:1563
 mount_fs+0x92/0x2a0 fs/super.c:1237
 vfs_kern_mount.part.0+0x5b/0x3c0 fs/namespace.c:1046
 vfs_kern_mount fs/namespace.c:1036 [inline]
 do_new_mount fs/namespace.c:2549 [inline]
 do_mount+0x3c9/0x25e0 fs/namespace.c:2879
 SYSC_mount fs/namespace.c:3095 [inline]
 SyS_mount+0xa8/0x120 fs/namespace.c:3072
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

Freed by task 6783:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0xaf/0x190 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3496 [inline]
 kfree+0xcb/0x260 mm/slab.c:3815
 kvfree+0x45/0x50 mm/util.c:416
 deactivate_locked_super+0x6c/0xd0 fs/super.c:319
 sget_userns+0x9df/0xc30 fs/super.c:537
 sget+0xd1/0x110 fs/super.c:572
 btrfs_mount+0x113c/0x2838 fs/btrfs/super.c:1610
 mount_fs+0x92/0x2a0 fs/super.c:1237
 vfs_kern_mount.part.0+0x5b/0x3c0 fs/namespace.c:1046
 vfs_kern_mount+0x3c/0x60 fs/namespace.c:1036
 mount_subvol fs/btrfs/super.c:1392 [inline]
 btrfs_mount+0x2a0/0x2838 fs/btrfs/super.c:1563
 mount_fs+0x92/0x2a0 fs/super.c:1237
 vfs_kern_mount.part.0+0x5b/0x3c0 fs/namespace.c:1046
 vfs_kern_mount fs/namespace.c:1036 [inline]
 do_new_mount fs/namespace.c:2549 [inline]
 do_mount+0x3c9/0x25e0 fs/namespace.c:2879
 SYSC_mount fs/namespace.c:3095 [inline]
 SyS_mount+0xa8/0x120 fs/namespace.c:3072
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

The buggy address belongs to the object at ffff8880a3c409c0
 which belongs to the cache kmalloc-16384 of size 16384
The buggy address is located 6296 bytes inside of
 16384-byte region [ffff8880a3c409c0, ffff8880a3c449c0)
The buggy address belongs to the page:
page:ffffea00028f1000 count:1 mapcount:0 mapping:ffff8880a3c409c0 index:0x0 compound_mapcount: 0
flags: 0xfffe0000008100(slab|head)
raw: 00fffe0000008100 ffff8880a3c409c0 0000000000000000 0000000100000001
raw: ffffea00022b4c20 ffffea000295bc20 ffff8880aa802200 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a3c42100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880a3c42180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880a3c42200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                    ^
 ffff8880a3c42280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880a3c42300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (13):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/07/09 00:55 linux-4.14.y b850307b279c 9f9845eb .config console log report syz C ci2-linux-4-14
2021/12/11 13:06 linux-4.14.y c01d4d1b885d 49ca1f59 .config console log report info ci2-linux-4-14 KASAN: use-after-free Read in btrfs_mount
2021/01/31 05:09 linux-4.14.y 2c8a3fceddf0 fc9fd31e .config console log report info ci2-linux-4-14 KASAN: use-after-free Read in btrfs_mount
2021/01/01 03:14 linux-4.14.y 1752938529c6 79264ae3 .config console log report info ci2-linux-4-14
2020/12/31 20:01 linux-4.14.y 1752938529c6 79264ae3 .config console log report info ci2-linux-4-14
2020/11/24 02:11 linux-4.14.y 0df445b0f0da 878fb17a .config console log report info ci2-linux-4-14
2020/11/21 20:34 linux-4.14.y 8961076ed318 c7ec2d19 .config console log report info ci2-linux-4-14
2020/11/02 06:07 linux-4.14.y 2b7915014161 8bc4594f .config console log report info ci2-linux-4-14
2020/09/25 02:54 linux-4.14.y cbfa1702aaf6 54289b08 .config console log report info ci2-linux-4-14
2020/09/15 15:55 linux-4.14.y cbfa1702aaf6 9e681632 .config console log report info ci2-linux-4-14
2020/07/09 00:27 linux-4.14.y b850307b279c 9f9845eb .config console log report ci2-linux-4-14
2020/07/07 06:03 linux-4.14.y b850307b279c ef278c73 .config console log report ci2-linux-4-14
2020/06/23 11:08 linux-4.14.y b850307b279c 1afe1535 .config console log report ci2-linux-4-14
* Struck through repros no longer work on HEAD.