syzbot


WARNING: suspicious RCU usage in shmem_fcntl

Status: auto-closed as invalid on 2020/03/02 08:33
Reported-by: syzbot+401108efb50b91e7df72@syzkaller.appspotmail.com
First crash: 1689d, last: 1689d

Sample crash report:
audit: type=1400 audit(1572769945.483:26): avc:  denied  { syslog } for  pid=4239 comm="syz-executor.0" capability=34  scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=capability2 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-executor.2/4237:
 #0:  (&sb->s_type->i_mutex_key#10){+.+.}, at: [<000000000a0b8d21>] inode_lock include/linux/fs.h:724 [inline]
 #0:  (&sb->s_type->i_mutex_key#10){+.+.}, at: [<000000000a0b8d21>] shmem_add_seals+0x12b/0xf80 mm/shmem.c:2831
 #1:  (&(&mapping->tree_lock)->rlock){-.-.}, at: [<00000000f5cff072>] spin_lock_irq include/linux/spinlock.h:342 [inline]
 #1:  (&(&mapping->tree_lock)->rlock){-.-.}, at: [<00000000f5cff072>] shmem_tag_pins mm/shmem.c:2685 [inline]
 #1:  (&(&mapping->tree_lock)->rlock){-.-.}, at: [<00000000f5cff072>] shmem_wait_for_pins mm/shmem.c:2726 [inline]
 #1:  (&(&mapping->tree_lock)->rlock){-.-.}, at: [<00000000f5cff072>] shmem_add_seals+0x2e1/0xf80 mm/shmem.c:2843

stack backtrace:
CPU: 0 PID: 4237 Comm: syz-executor.2 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
 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: 0033:0x459f49
RSP: 002b:00007fda0173cc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000048
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459f49
RDX: 0000000000000009 RSI: 0000000000000409 RDI: 0000000000000006
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fda0173d6d4
R13: 00000000004c0904 R14: 00000000004d31f0 R15: 00000000ffffffff
audit: type=1400 audit(1572769945.523:27): avc:  denied  { map } for  pid=4249 comm="syz-executor.0" path="/root/syzkaller-testdir784551788/syzkaller.EfL6PQ/7/file0/bus" dev="ramfs" ino=10520 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=system_u:object_r:ramfs_t:s0 tclass=file permissive=1
audit: type=1400 audit(1572769945.753:28): avc:  denied  { map } for  pid=4267 comm="syz-executor.4" path="/dev/loop0" dev="devtmpfs" ino=1059 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=system_u:object_r:fixed_disk_device_t:s0 tclass=blk_file permissive=1
netlink: 188 bytes leftover after parsing attributes in process `syz-executor.1'.
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=4313 comm=syz-executor.1
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=4313 comm=syz-executor.1
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=4313 comm=syz-executor.1
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=4313 comm=syz-executor.1
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=4313 comm=syz-executor.1
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=4313 comm=syz-executor.1
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=4313 comm=syz-executor.1
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=4313 comm=syz-executor.1
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=4313 comm=syz-executor.1
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=4313 comm=syz-executor.1
input: syz1 as /devices/virtual/input/input11
input: syz1 as /devices/virtual/input/input12
audit: type=1400 audit(1572769948.313:29): avc:  denied  { create } for  pid=4419 comm="syz-executor.0" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_netfilter_socket permissive=1
audit: type=1400 audit(1572769948.353:30): avc:  denied  { sys_admin } for  pid=4419 comm="syz-executor.0" capability=21  scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=cap_userns permissive=1
audit: type=1400 audit(1572769948.723:31): avc:  denied  { dac_override } for  pid=4429 comm="syz-executor.0" capability=1  scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=cap_userns permissive=1
audit: type=1400 audit(1572769949.123:32): avc:  denied  { mac_admin } for  pid=4437 comm="syz-executor.4" capability=33  scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=capability2 permissive=1
SELinux:  Context unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 is not valid (left unmapped).
 loop3: p1 < > p4
loop3: p1 size 2 extends beyond EOD, truncated
loop3: p4 start 1854537728 is beyond EOD, truncated
 loop3: p1 < > p4
loop3: p1 size 2 extends beyond EOD, truncated
loop3: p4 start 1854537728 is beyond EOD, truncated
audit: type=1400 audit(1572769950.153:33): avc:  denied  { dyntransition } for  pid=4515 comm="syz-executor.1" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0 tclass=process permissive=1
input: syz1 as /devices/virtual/input/input13
audit: type=1400 audit(1572769950.683:34): avc:  denied  { dyntransition } for  pid=4515 comm="syz-executor.1" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0 tclass=process permissive=1
input: syz1 as /devices/virtual/input/input14
audit: type=1400 audit(1572769952.263:35): avc:  denied  { ioctl } for  pid=4548 comm="syz-executor.4" path="socket:[11983]" dev="sockfs" ino=11983 ioctlcmd=0x8946 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=1
selinux_nlmsg_perm: 853 callbacks suppressed
SELinux: unrecognized netlink message: protocol=4 nlmsg_type=21549 sclass=netlink_tcpdiag_socket pig=4744 comm=syz-executor.4
SELinux: unrecognized netlink message: protocol=4 nlmsg_type=21549 sclass=netlink_tcpdiag_socket pig=4744 comm=syz-executor.4
SELinux: unrecognized netlink message: protocol=4 nlmsg_type=21549 sclass=netlink_tcpdiag_socket pig=4760 comm=syz-executor.4
audit: type=1400 audit(1572769954.253:36): avc:  denied  { getattr } for  pid=4787 comm="syz-executor.0" path="socket:[12131]" dev="sockfs" ino=12131 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=1
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=18873 sclass=netlink_route_socket pig=4783 comm=syz-executor.5
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=18873 sclass=netlink_route_socket pig=4783 comm=syz-executor.5

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2019/11/03 08:32 android-4.14 6409e7e01d11 a41ca8fa .config console log report ci-android-414-kasan-gce-root
* Struck through repros no longer work on HEAD.