syzbot


WARNING: suspicious RCU usage in shmem_add_seals

Status: public: reported C repro on 2019/10/30 10:43
Reported-by: syzbot+fbb9e2ae57043cb180e4@syzkaller.appspotmail.com
First crash: 1806d, last: 1785d
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.14 WARNING: suspicious RCU usage in shmem_add_seals C done done 1435 1785d 1807d 1/1 fixed on 2019/12/21 01:54

Sample crash report:
urandom_read: 2 callbacks suppressed
random: sshd: uninitialized urandom read (32 bytes read)
audit: type=1400 audit(1572771949.516:7): avc:  denied  { map } for  pid=1771 comm="syz-executor465" path="/root/syz-executor465108009" dev="sda1" ino=16483 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1
=============================
WARNING: suspicious RCU usage
4.14.151+ #0 Not tainted
-----------------------------
./include/linux/radix-tree.h:238 suspicious rcu_dereference_check() usage!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 1
2 locks held by syz-executor465/1771:
 #0:  (&sb->s_type->i_mutex_key#10){+.+.}, at: [<        (ptrval)>] inode_lock include/linux/fs.h:724 [inline]
 #0:  (&sb->s_type->i_mutex_key#10){+.+.}, at: [<        (ptrval)>] shmem_add_seals+0x12b/0xf80 mm/shmem.c:2831
 #1:  (&(&mapping->tree_lock)->rlock){-...}, at: [<        (ptrval)>] spin_lock_irq include/linux/spinlock.h:342 [inline]
 #1:  (&(&mapping->tree_lock)->rlock){-...}, at: [<        (ptrval)>] shmem_tag_pins mm/shmem.c:2685 [inline]
 #1:  (&(&mapping->tree_lock)->rlock){-...}, at: [<        (ptrval)>] shmem_wait_for_pins mm/shmem.c:2726 [inline]
 #1:  (&(&mapping->tree_lock)->rlock){-...}, at: [<        (ptrval)>] shmem_add_seals+0x2e1/0xf80 mm/shmem.c:2843

stack backtrace:
CPU: 0 PID: 1771 Comm: syz-executor465 Not tainted 4.14.151+ #0
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0xca/0x134 lib/dump_stack.c:53
 radix_tree_deref_slot include/linux/radix-tree.h:238 [inline]
 shmem_tag_pins mm/shmem.c:2687 [inline]
 shmem_wait_for_pins mm/shmem.c:2726 [inline]
 shmem_add_seals+0x9d2/0xf80 mm/shmem.c:2843
 shmem_fcntl+0xea/0x120 mm/shmem.c:2878
 do_fcntl+0x5c8/0xd20 fs/fcntl.c:421
 SYSC_fcntl fs/fcntl.c:463 [inline]
 SyS_fcntl+0xc6/0x100 fs/fcntl.c:448
 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x4401b9
RSP: 002b:00007ffeb659a198 EFLAGS: 00000246 ORIG_RAX: 0000000000000048
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004401b9
RDX: 0000000000000009 RSI: 0000000000000409 RDI: 0000000000000003
RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401a40

Crashes (7728):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2019/11/03 09:08 android-4.14 6409e7e01d11 a41ca8fa .config console log report syz C ci-android-414-kasan-gce-root
2019/11/03 01:05 android-4.14 6409e7e01d11 a41ca8fa .config console log report syz C ci-android-414-kasan-gce-root
2019/11/03 00:51 android-4.14 6409e7e01d11 a41ca8fa .config console log report syz C ci-android-414-kasan-gce-root
2019/11/03 00:25 android-4.14 6409e7e01d11 a41ca8fa .config console log report syz C ci-android-414-kasan-gce-root
2019/11/02 23:59 android-4.14 6409e7e01d11 a41ca8fa .config console log report syz C ci-android-414-kasan-gce-root
2019/11/02 23:44 android-4.14 6409e7e01d11 a41ca8fa .config console log report syz C ci-android-414-kasan-gce-root
2019/11/02 23:31 android-4.14 6409e7e01d11 a41ca8fa .config console log report syz C ci-android-414-kasan-gce-root
2019/11/01 06:41 android-4.14 6409e7e01d11 a41ca8fa .config console log report syz C ci-android-414-kasan-gce-root
2019/10/30 11:43 android-4.14 2bb70f40b08b 5ea87a66 .config console log report syz C ci-android-414-kasan-gce-root
2019/11/20 20:16 android-4.14 460dc7c31cef 8098ea0f .config console log report ci-android-414-kasan-gce-root
2019/11/20 18:59 android-4.14 460dc7c31cef f4b7ed07 .config console log report ci-android-414-kasan-gce-root
2019/11/20 17:53 android-4.14 460dc7c31cef f4b7ed07 .config console log report ci-android-414-kasan-gce-root
2019/11/20 16:41 android-4.14 460dc7c31cef f4b7ed07 .config console log report ci-android-414-kasan-gce-root
2019/11/20 15:41 android-4.14 460dc7c31cef f4b7ed07 .config console log report ci-android-414-kasan-gce-root
2019/11/20 14:26 android-4.14 460dc7c31cef f4b7ed07 .config console log report ci-android-414-kasan-gce-root
2019/11/20 13:23 android-4.14 460dc7c31cef f4b7ed07 .config console log report ci-android-414-kasan-gce-root
2019/11/20 12:04 android-4.14 460dc7c31cef f4b7ed07 .config console log report ci-android-414-kasan-gce-root
2019/11/20 10:50 android-4.14 460dc7c31cef f4b7ed07 .config console log report ci-android-414-kasan-gce-root
2019/11/20 09:45 android-4.14 460dc7c31cef f4b7ed07 .config console log report ci-android-414-kasan-gce-root
2019/11/20 07:14 android-4.14 460dc7c31cef f4b7ed07 .config console log report ci-android-414-kasan-gce-root
2019/11/20 05:41 android-4.14 460dc7c31cef f4b7ed07 .config console log report ci-android-414-kasan-gce-root
2019/11/20 04:20 android-4.14 460dc7c31cef f4b7ed07 .config console log report ci-android-414-kasan-gce-root
2019/11/20 02:55 android-4.14 460dc7c31cef f4b7ed07 .config console log report ci-android-414-kasan-gce-root
2019/11/20 01:43 android-4.14 460dc7c31cef 5bc70212 .config console log report ci-android-414-kasan-gce-root
2019/11/20 00:22 android-4.14 460dc7c31cef 5bc70212 .config console log report ci-android-414-kasan-gce-root
2019/11/19 22:22 android-4.14 460dc7c31cef 5bc70212 .config console log report ci-android-414-kasan-gce-root
2019/11/19 22:02 android-4.14 460dc7c31cef 5bc70212 .config console log report ci-android-414-kasan-gce-root
2019/11/19 20:52 android-4.14 460dc7c31cef 5bc70212 .config console log report ci-android-414-kasan-gce-root
2019/11/19 19:21 android-4.14 460dc7c31cef 5bc70212 .config console log report ci-android-414-kasan-gce-root
2019/11/19 18:03 android-4.14 460dc7c31cef 5bc70212 .config console log report ci-android-414-kasan-gce-root
2019/11/19 17:32 android-4.14 460dc7c31cef 5bc70212 .config console log report ci-android-414-kasan-gce-root
2019/11/19 16:18 android-4.14 460dc7c31cef 5bc70212 .config console log report ci-android-414-kasan-gce-root
2019/11/19 15:18 android-4.14 460dc7c31cef 5bc70212 .config console log report ci-android-414-kasan-gce-root
2019/11/19 14:04 android-4.14 460dc7c31cef 5bc70212 .config console log report ci-android-414-kasan-gce-root
2019/11/19 13:42 android-4.14 460dc7c31cef 5bc70212 .config console log report ci-android-414-kasan-gce-root
2019/11/19 12:26 android-4.14 460dc7c31cef 5bc70212 .config console log report ci-android-414-kasan-gce-root
2019/11/19 11:18 android-4.14 460dc7c31cef 5bc70212 .config console log report ci-android-414-kasan-gce-root
2019/11/19 10:09 android-4.14 460dc7c31cef 5bc70212 .config console log report ci-android-414-kasan-gce-root
2019/11/19 09:06 android-4.14 460dc7c31cef 5bc70212 .config console log report ci-android-414-kasan-gce-root
2019/11/19 06:56 android-4.14 460dc7c31cef 5bc70212 .config console log report ci-android-414-kasan-gce-root
2019/11/19 05:39 android-4.14 460dc7c31cef 5bc70212 .config console log report ci-android-414-kasan-gce-root
2019/11/19 03:21 android-4.14 460dc7c31cef 5bc70212 .config console log report ci-android-414-kasan-gce-root
2019/11/19 02:24 android-4.14 460dc7c31cef 5bc70212 .config console log report ci-android-414-kasan-gce-root
2019/11/19 01:00 android-4.14 460dc7c31cef 5bc70212 .config console log report ci-android-414-kasan-gce-root
2019/11/18 23:37 android-4.14 460dc7c31cef 1daed50a .config console log report ci-android-414-kasan-gce-root
2019/11/18 22:15 android-4.14 460dc7c31cef 1daed50a .config console log report ci-android-414-kasan-gce-root
2019/11/18 20:45 android-4.14 460dc7c31cef 1daed50a .config console log report ci-android-414-kasan-gce-root
2019/11/18 19:28 android-4.14 460dc7c31cef 1daed50a .config console log report ci-android-414-kasan-gce-root
2019/11/18 19:28 android-4.14 460dc7c31cef 1daed50a .config console log report ci-android-414-kasan-gce-root
2019/11/18 18:07 android-4.14 460dc7c31cef 1daed50a .config console log report ci-android-414-kasan-gce-root
2019/11/18 15:57 android-4.14 460dc7c31cef 1daed50a .config console log report ci-android-414-kasan-gce-root
2019/10/30 10:37 android-4.14 2bb70f40b08b 5ea87a66 .config console log report ci-android-414-kasan-gce-root
* Struck through repros no longer work on HEAD.