ion_buffer_create drivers/staging/android/ion/ion.c:94 [inline] ion_alloc+0x1e9/0x7d0 drivers/staging/android/ion/ion.c:425 ion_ioctl+0xef/0x1f8 drivers/staging/android/ion/ion-ioctl.c:87 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x75a/0xfe0 fs/ioctl.c:684 ====================================================== SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692 WARNING: possible circular locking dependency detected 4.14.176-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.0/21084 is trying to acquire lock: do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 ( entry_SYSCALL_64_after_hwframe+0x42/0xb7 &p->lock RIP: 0033:0x45c889 ){+.+.} RSP: 002b:00007f3f74f6ac78 EFLAGS: 00000246 , at: [] seq_read+0xba/0x1160 fs/seq_file.c:165 ORIG_RAX: 0000000000000010 but task is already holding lock: RAX: ffffffffffffffda RBX: 00007f3f74f6b6d4 RCX: 000000000045c889 ( RDX: 0000000020000000 RSI: 00000000c0184900 RDI: 0000000000000004 sb_writers#3 RBP: 000000000076bf00 R08: 0000000000000000 R09: 0000000000000000 ){.+.+} R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff , at: [] file_start_write include/linux/fs.h:2708 [inline] , at: [] do_sendfile+0x865/0xaf0 fs/read_write.c:1440 R13: 0000000000000366 R14: 00000000004c5db0 R15: 000000000076bf0c which lock already depends on the new lock. Mem-Info: the existing dependency chain (in reverse order) is: -> #3 (sb_writers#3){.+.+}: percpu_down_read_preempt_disable include/linux/percpu-rwsem.h:36 [inline] percpu_down_read include/linux/percpu-rwsem.h:59 [inline] __sb_start_write+0x1a1/0x2e0 fs/super.c:1363 sb_start_write include/linux/fs.h:1549 [inline] mnt_want_write+0x3a/0xb0 fs/namespace.c:386 ovl_create_object+0x75/0x1d0 fs/overlayfs/dir.c:538 active_anon:380558 inactive_anon:6085 isolated_anon:12 active_file:13606 inactive_file:13566 isolated_file:44 unevictable:0 dirty:314 writeback:0 unstable:0 slab_reclaimable:17509 slab_unreclaimable:133892 mapped:64225 shmem:6264 pagetables:5564 bounce:0 free:942582 free_pcp:183 free_cma:0 lookup_open+0x10e8/0x1750 fs/namei.c:3241 do_last fs/namei.c:3334 [inline] path_openat+0xfc1/0x3c50 fs/namei.c:3569 do_filp_open+0x18e/0x250 fs/namei.c:3603 do_sys_open+0x29d/0x3f0 fs/open.c:1081 Node 0 active_anon:1486240kB inactive_anon:16132kB active_file:54212kB inactive_file:54236kB unevictable:0kB isolated(anon):48kB isolated(file):176kB mapped:256092kB dirty:1204kB writeback:0kB shmem:16844kB shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 1155072kB writeback_tmp:0kB unstable:0kB all_unreclaimable? no do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 -> #2 Node 0 ( DMA free:10424kB min:220kB low:272kB high:324kB active_anon:4104kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:15992kB managed:15908kB mlocked:0kB kernel_stack:32kB pagetables:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB &ovl_i_mutex_dir_key[depth] lowmem_reserve[]: ){++++}: down_read+0x37/0xa0 kernel/locking/rwsem.c:24 inode_lock_shared include/linux/fs.h:729 [inline] do_last fs/namei.c:3333 [inline] path_openat+0x185a/0x3c50 fs/namei.c:3569 0 do_filp_open+0x18e/0x250 fs/namei.c:3603 do_open_execat+0xda/0x430 fs/exec.c:849 do_execveat_common.isra.0+0x694/0x1c70 fs/exec.c:1740 2557 do_execve fs/exec.c:1847 [inline] SYSC_execve fs/exec.c:1928 [inline] SyS_execve+0x34/0x40 fs/exec.c:1923 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 2557 -> #1 2557 (&sig->cred_guard_mutex){+.+.}: __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xe8/0x1470 kernel/locking/mutex.c:893 lock_trace+0x3f/0xc0 fs/proc/base.c:407 2557 proc_pid_syscall+0x81/0x1f0 fs/proc/base.c:639 proc_single_show+0xe7/0x150 fs/proc/base.c:761 seq_read+0x4d2/0x1160 fs/seq_file.c:237 do_loop_readv_writev fs/read_write.c:695 [inline] do_loop_readv_writev fs/read_write.c:682 [inline] do_iter_read+0x3e3/0x5a0 fs/read_write.c:919 vfs_readv+0xd3/0x130 fs/read_write.c:981 do_preadv+0x161/0x200 fs/read_write.c:1065 Node 0 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 -> #0 DMA32 free:76752kB min:36272kB low:45340kB high:54408kB active_anon:1481836kB inactive_anon:16132kB active_file:54772kB inactive_file:54764kB unevictable:0kB writepending:1204kB present:3129332kB managed:2621268kB mlocked:0kB kernel_stack:11872kB pagetables:21356kB bounce:0kB free_pcp:732kB local_pcp:0kB free_cma:0kB (&p->lock lowmem_reserve[]: ){+.+.} 0 : 0 lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3994 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xe8/0x1470 kernel/locking/mutex.c:893 seq_read+0xba/0x1160 fs/seq_file.c:165 0 do_loop_readv_writev fs/read_write.c:695 [inline] do_loop_readv_writev fs/read_write.c:682 [inline] do_iter_read+0x3e3/0x5a0 fs/read_write.c:919 0 vfs_readv+0xd3/0x130 fs/read_write.c:981 0 kernel_readv fs/splice.c:361 [inline] default_file_splice_read+0x41d/0x870 fs/splice.c:416 do_splice_to+0xfb/0x150 fs/splice.c:880 Node 0 splice_direct_to_actor+0x20a/0x730 fs/splice.c:952 do_splice_direct+0x164/0x210 fs/splice.c:1061 do_sendfile+0x469/0xaf0 fs/read_write.c:1441 Normal free:0kB min:4kB low:4kB high:4kB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:786432kB managed:348kB mlocked:0kB kernel_stack:0kB pagetables:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB SYSC_sendfile64 fs/read_write.c:1502 [inline] SyS_sendfile64+0xff/0x110 fs/read_write.c:1488 lowmem_reserve[]: do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 0 entry_SYSCALL_64_after_hwframe+0x42/0xb7 0 other info that might help us debug this: 0 Chain exists of: 0 0 &p->lock --> &ovl_i_mutex_dir_key[depth] --> sb_writers#3 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(sb_writers#3); lock( Node 0 &ovl_i_mutex_dir_key[depth]); lock(sb_writers#3); lock(&p->lock); *** DEADLOCK *** 1 lock held by syz-executor.0/21084: #0: ( DMA: sb_writers 4*4kB #3 (UM) ){.+.+}, at: [] file_start_write include/linux/fs.h:2708 [inline] ){.+.+}, at: [] do_sendfile+0x865/0xaf0 fs/read_write.c:1440 stack backtrace: 6*8kB CPU: 0 PID: 21084 Comm: syz-executor.0 Not tainted 4.14.176-syzkaller #0 (UH) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 3*16kB Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x13e/0x194 lib/dump_stack.c:58 (UM) print_circular_bug.isra.0.cold+0x1c4/0x282 kernel/locking/lockdep.c:1258 check_prev_add kernel/locking/lockdep.c:1901 [inline] check_prevs_add kernel/locking/lockdep.c:2018 [inline] validate_chain kernel/locking/lockdep.c:2460 [inline] __lock_acquire+0x2cb3/0x4620 kernel/locking/lockdep.c:3487 3*32kB lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3994 (UMH) 2*64kB __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xe8/0x1470 kernel/locking/mutex.c:893 (MH) 1*128kB (M) 1*256kB (M) 1*512kB (M) seq_read+0xba/0x1160 fs/seq_file.c:165 1*1024kB (M) 0*2048kB do_loop_readv_writev fs/read_write.c:695 [inline] do_loop_readv_writev fs/read_write.c:682 [inline] do_iter_read+0x3e3/0x5a0 fs/read_write.c:919 vfs_readv+0xd3/0x130 fs/read_write.c:981 2*4096kB (UE) = 10448kB Node 0 kernel_readv fs/splice.c:361 [inline] default_file_splice_read+0x41d/0x870 fs/splice.c:416 DMA32: 5098*4kB (UMEH) 1845*8kB (UMEH) 1045*16kB (UMEH) 777*32kB (UMEH) 2*64kB do_splice_to+0xfb/0x150 fs/splice.c:880 (H) splice_direct_to_actor+0x20a/0x730 fs/splice.c:952 1*128kB (H) 0*256kB 0*512kB do_splice_direct+0x164/0x210 fs/splice.c:1061 0*1024kB 0*2048kB 0*4096kB = 76992kB do_sendfile+0x469/0xaf0 fs/read_write.c:1441 SYSC_sendfile64 fs/read_write.c:1502 [inline] SyS_sendfile64+0xff/0x110 fs/read_write.c:1488 Node 0 Normal: 0*4kB do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 0*8kB entry_SYSCALL_64_after_hwframe+0x42/0xb7 0*16kB RIP: 0033:0x45c889 0*32kB RSP: 002b:00007f722ab5cc78 EFLAGS: 00000246 0*64kB ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007f722ab5d6d4 RCX: 000000000045c889 RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000007 RBP: 000000000076bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000209 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000008d6 R14: 00000000004cb7ee R15: 000000000076bf0c minix_free_inode: bit 1 already cleared 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 0kB Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=1048576kB Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=2048kB Node 1 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=1048576kB Node 1 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=2048kB 31068 total pagecache pages 0 pages in swap cache Swap cache stats: add 0, delete 0, find 0/0 Free swap = 0kB Total swap = 0kB 1965979 pages RAM 0 pages HighMem/MovableOnly 339050 pages reserved 0 pages cma reserved BFS-fs: bfs_fill_super(): No BFS filesystem on nullb0 (magic=00000000) BFS-fs: bfs_fill_super(): No BFS filesystem on nullb0 (magic=39313a57) BFS-fs: bfs_fill_super(): No BFS filesystem on nullb0 (magic=00000000) BFS-fs: bfs_fill_super(): No BFS filesystem on nullb0 (magic=00000000) BFS-fs: bfs_fill_super(): No BFS filesystem on nullb0 (magic=00000000) BFS-fs: bfs_fill_super(): No BFS filesystem on nullb0 (magic=00000000) BFS-fs: bfs_fill_super(): No BFS filesystem on nullb0 (magic=00000000) BFS-fs: bfs_fill_super(): No BFS filesystem on nullb0 (magic=00000000) kauditd_printk_skb: 60 callbacks suppressed audit: type=1804 audit(1586819483.465:30214): pid=21348 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.1" name="/root/syzkaller-testdir128195168/syzkaller.lBVEo5/384/file0" dev="sda1" ino=16209 res=1 xt_nfacct: accounting object with name `syz1' does not exists ip_tables: iptables: counters copy to user failed while replacing table audit: type=1804 audit(1586819483.885:30215): pid=21387 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.1" name="/root/syzkaller-testdir128195168/syzkaller.lBVEo5/385/file0" dev="sda1" ino=16258 res=1 xt_nfacct: accounting object with name `syz1' does not exists audit: type=1804 audit(1586819483.995:30216): pid=21395 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.1" name="/root/syzkaller-testdir128195168/syzkaller.lBVEo5/386/file0" dev="sda1" ino=16260 res=1 xt_nfacct: accounting object with name `syz1' does not exists xt_nfacct: accounting object with name `syz1' does not exists audit: type=1804 audit(1586819484.155:30217): pid=21412 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="open_writers" comm="syz-executor.1" name="/root/syzkaller-testdir128195168/syzkaller.lBVEo5/387/file0" dev="sda1" ino=16226 res=1 ip_tables: iptables: counters copy to user failed while replacing table ip_tables: iptables: counters copy to user failed while replacing table ip_tables: iptables: counters copy to user failed while replacing table ip_tables: iptables: counters copy to user failed while replacing table ip_tables: iptables: counters copy to user failed while replacing table