syzbot


KASAN: use-after-free Read in iput

Status: fixed on 2018/07/08 03:16
Subsystems: fuse
[Documentation on labels]
Reported-by: syzbot+c6f45f6af72a45097be2@syzkaller.appspotmail.com
Fix commit: 0c92c7a3c5d4 tracing: Fix bad use of igrab in trace_uprobe.c
First crash: 2286d, last: 2286d
Discussions (1)
Title Replies (including bot) Last reply
KASAN: use-after-free Read in iput 1 (2) 2018/07/08 00:59
Similar bugs (2)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-49 KASAN: use-after-free Read in iput 1 1992d 1924d 0/3 auto-closed as invalid on 2019/08/05 02:50
upstream KASAN: use-after-free Read in iput (2) gfs2 6 1132d 1336d 0/27 auto-closed as invalid on 2021/10/12 21:28

Sample crash report:
VFS: Busy inodes after unmount of fuse. Self-destruct in 5 seconds.  Have a nice day...
==================================================================
BUG: KASAN: use-after-free in iput_final fs/inode.c:1489 [inline]
BUG: KASAN: use-after-free in iput+0xa05/0xa80 fs/inode.c:1545
Read of size 8 at addr ffff8801d9752770 by task syzkaller802106/4482

CPU: 1 PID: 4482 Comm: syzkaller802106 Not tainted 4.17.0-rc1+ #6
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1b9/0x294 lib/dump_stack.c:113
 print_address_description+0x6c/0x20b mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.7+0x242/0x2fe mm/kasan/report.c:412
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
 iput_final fs/inode.c:1489 [inline]
 iput+0xa05/0xa80 fs/inode.c:1545
 free_trace_uprobe+0xe2/0x1f0 kernel/trace/trace_uprobe.c:292
 destroy_local_trace_uprobe+0x63/0x7e kernel/trace/trace_uprobe.c:1395
 perf_uprobe_destroy+0xf2/0x130 kernel/trace/trace_event_perf.c:342
 _free_event+0x3ff/0x1430 kernel/events/core.c:4445
 put_event+0x48/0x60 kernel/events/core.c:4531
 perf_event_release_kernel+0x8bd/0xf90 kernel/events/core.c:4637
 perf_release+0x37/0x50 kernel/events/core.c:4647
 __fput+0x34d/0x890 fs/file_table.c:209
 ____fput+0x15/0x20 fs/file_table.c:243
 task_work_run+0x1e4/0x290 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0x1aee/0x2730 kernel/exit.c:865
 do_group_exit+0x16f/0x430 kernel/exit.c:968
 get_signal+0x886/0x1960 kernel/signal.c:2469
 do_signal+0x98/0x2040 arch/x86/kernel/signal.c:810
 exit_to_usermode_loop+0x28a/0x310 arch/x86/entry/common.c:162
 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:265 [inline]
 do_syscall_64+0x6ac/0x800 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4457b9
RSP: 002b:00007f98cec58da8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 0000000000000000 RCX: 00000000004457b9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000006dac3c
RBP: 00000000006dac3c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dac38
R13: 0030656c69662f2e R14: 00007f98cec599c0 R15: 0000000000000001

Allocated by task 4481:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:553
 kmem_cache_alloc_trace+0x152/0x780 mm/slab.c:3620
 kmalloc include/linux/slab.h:512 [inline]
 kzalloc include/linux/slab.h:701 [inline]
 alloc_super fs/super.c:186 [inline]
 sget_userns+0x1c7/0xf20 fs/super.c:503
 sget+0x10b/0x150 fs/super.c:558
 mount_nodev+0x33/0x110 fs/super.c:1206
 fuse_mount+0x2c/0x40 fs/fuse/inode.c:1192
 mount_fs+0xae/0x328 fs/super.c:1268
 vfs_kern_mount.part.34+0xd4/0x4d0 fs/namespace.c:1037
 vfs_kern_mount fs/namespace.c:1027 [inline]
 do_new_mount fs/namespace.c:2517 [inline]
 do_mount+0x564/0x3070 fs/namespace.c:2847
 ksys_mount+0x12d/0x140 fs/namespace.c:3063
 __do_sys_mount fs/namespace.c:3077 [inline]
 __se_sys_mount fs/namespace.c:3074 [inline]
 __x64_sys_mount+0xbe/0x150 fs/namespace.c:3074
 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 25:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:521
 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
 __cache_free mm/slab.c:3498 [inline]
 kfree+0xd9/0x260 mm/slab.c:3813
 destroy_super_work+0x40/0x50 fs/super.c:149
 process_one_work+0xc1e/0x1b50 kernel/workqueue.c:2145
 worker_thread+0x1cc/0x1440 kernel/workqueue.c:2279
 kthread+0x345/0x410 kernel/kthread.c:238
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412

The buggy address belongs to the object at ffff8801d9752740
 which belongs to the cache kmalloc-4096 of size 4096
The buggy address is located 48 bytes inside of
 4096-byte region [ffff8801d9752740, ffff8801d9753740)
The buggy address belongs to the page:
page:ffffea000765d480 count:1 mapcount:0 mapping:ffff8801d9752740 index:0x0 compound_mapcount: 0
flags: 0x2fffc0000008100(slab|head)
raw: 02fffc0000008100 ffff8801d9752740 0000000000000000 0000000100000001
raw: ffffea000765a1a0 ffffea00076665a0 ffff8801dac00dc0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801d9752600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8801d9752680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8801d9752700: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
                                                             ^
 ffff8801d9752780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801d9752800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2018/04/17 19:32 upstream a27fc14219f2 b80fd3b5 .config console log report syz C ci-upstream-kasan-gce-root
2018/04/17 19:09 upstream a27fc14219f2 b80fd3b5 .config console log report ci-upstream-kasan-gce-root
* Struck through repros no longer work on HEAD.