====================================================== WARNING: possible circular locking dependency detected 4.14.275-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.1/9580 is trying to acquire lock: (sb_writers#6){.+.+}, at: [] file_start_write include/linux/fs.h:2714 [inline] (sb_writers#6){.+.+}, at: [] vfs_fallocate+0x5c1/0x790 fs/open.c:318 but task is already holding lock: (ashmem_mutex){+.+.}, at: [] ashmem_shrink_scan+0x3f/0x80 drivers/staging/android/ashmem.c:494 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (ashmem_mutex){+.+.}: __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893 ashmem_mmap+0x50/0x5c0 drivers/staging/android/ashmem.c:393 call_mmap include/linux/fs.h:1785 [inline] mmap_region+0xa1a/0x1220 mm/mmap.c:1717 do_mmap+0x5b3/0xcb0 mm/mmap.c:1495 do_mmap_pgoff include/linux/mm.h:2185 [inline] vm_mmap_pgoff+0x14e/0x1a0 mm/util.c:333 SYSC_mmap_pgoff mm/mmap.c:1545 [inline] SyS_mmap_pgoff+0x249/0x510 mm/mmap.c:1503 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb -> #2 (&mm->mmap_sem){++++}: __might_fault mm/memory.c:4687 [inline] __might_fault+0x137/0x1b0 mm/memory.c:4672 _copy_to_user+0x27/0xd0 lib/usercopy.c:25 copy_to_user include/linux/uaccess.h:155 [inline] filldir+0x1d5/0x390 fs/readdir.c:237 dir_emit_dot include/linux/fs.h:3361 [inline] dir_emit_dots include/linux/fs.h:3372 [inline] dcache_readdir+0x180/0x860 fs/libfs.c:192 iterate_dir+0x1a0/0x5e0 fs/readdir.c:52 SYSC_getdents fs/readdir.c:272 [inline] SyS_getdents+0x125/0x240 fs/readdir.c:253 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb -> #1 (&type->i_mutex_dir_key#5){++++}: down_write+0x34/0x90 kernel/locking/rwsem.c:54 inode_lock include/linux/fs.h:719 [inline] do_last fs/namei.c:3331 [inline] path_openat+0xde2/0x2970 fs/namei.c:3569 do_filp_open+0x179/0x3c0 fs/namei.c:3603 do_sys_open+0x296/0x410 fs/open.c:1081 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb -> #0 (sb_writers#6){.+.+}: lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998 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+0x64/0x260 fs/super.c:1342 file_start_write include/linux/fs.h:2714 [inline] vfs_fallocate+0x5c1/0x790 fs/open.c:318 ashmem_shrink_scan.part.0+0x135/0x3d0 drivers/staging/android/ashmem.c:501 ashmem_shrink_scan+0x50/0x80 drivers/staging/android/ashmem.c:494 do_shrink_slab mm/vmscan.c:401 [inline] shrink_slab+0x535/0xb60 mm/vmscan.c:504 drop_slab_node+0x2b/0x60 mm/vmscan.c:531 drop_slab+0x39/0x70 mm/vmscan.c:542 drop_caches_sysctl_handler+0xc9/0xe0 fs/drop_caches.c:65 proc_sys_call_handler.isra.0+0x1ba/0x340 fs/proc/proc_sysctl.c:598 __vfs_write+0xe4/0x630 fs/read_write.c:480 __kernel_write+0xf5/0x330 fs/read_write.c:501 write_pipe_buf+0x143/0x1c0 fs/splice.c:797 splice_from_pipe_feed fs/splice.c:502 [inline] __splice_from_pipe+0x326/0x7a0 fs/splice.c:626 splice_from_pipe fs/splice.c:661 [inline] default_file_splice_write+0xc5/0x150 fs/splice.c:809 do_splice_from fs/splice.c:851 [inline] direct_splice_actor+0x115/0x160 fs/splice.c:1018 splice_direct_to_actor+0x27c/0x730 fs/splice.c:973 do_splice_direct+0x164/0x210 fs/splice.c:1061 do_sendfile+0x47f/0xb30 fs/read_write.c:1441 SYSC_sendfile64 fs/read_write.c:1502 [inline] SyS_sendfile64+0xff/0x110 fs/read_write.c:1488 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb other info that might help us debug this: Chain exists of: sb_writers#6 --> &mm->mmap_sem --> ashmem_mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(ashmem_mutex); lock(&mm->mmap_sem); lock(ashmem_mutex); lock(sb_writers#6); *** DEADLOCK *** 3 locks held by syz-executor.1/9580: #0: (sb_writers#4){.+.+}, at: [] file_start_write include/linux/fs.h:2714 [inline] #0: (sb_writers#4){.+.+}, at: [] do_sendfile+0x84f/0xb30 fs/read_write.c:1440 #1: (shrinker_rwsem){++++}, at: [] shrink_slab+0x13b/0xb60 mm/vmscan.c:474 #2: (ashmem_mutex){+.+.}, at: [] ashmem_shrink_scan+0x3f/0x80 drivers/staging/android/ashmem.c:494 stack backtrace: CPU: 1 PID: 9580 Comm: syz-executor.1 Not tainted 4.14.275-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+0x1b2/0x281 lib/dump_stack.c:58 print_circular_bug.constprop.0.cold+0x2d7/0x41e kernel/locking/lockdep.c:1258 check_prev_add kernel/locking/lockdep.c:1905 [inline] check_prevs_add kernel/locking/lockdep.c:2022 [inline] validate_chain kernel/locking/lockdep.c:2464 [inline] __lock_acquire+0x2e0e/0x3f20 kernel/locking/lockdep.c:3491 lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998 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+0x64/0x260 fs/super.c:1342 file_start_write include/linux/fs.h:2714 [inline] vfs_fallocate+0x5c1/0x790 fs/open.c:318 ashmem_shrink_scan.part.0+0x135/0x3d0 drivers/staging/android/ashmem.c:501 ashmem_shrink_scan+0x50/0x80 drivers/staging/android/ashmem.c:494 do_shrink_slab mm/vmscan.c:401 [inline] shrink_slab+0x535/0xb60 mm/vmscan.c:504 drop_slab_node+0x2b/0x60 mm/vmscan.c:531 drop_slab+0x39/0x70 mm/vmscan.c:542 drop_caches_sysctl_handler+0xc9/0xe0 fs/drop_caches.c:65 proc_sys_call_handler.isra.0+0x1ba/0x340 fs/proc/proc_sysctl.c:598 __vfs_write+0xe4/0x630 fs/read_write.c:480 __kernel_write+0xf5/0x330 fs/read_write.c:501 write_pipe_buf+0x143/0x1c0 fs/splice.c:797 splice_from_pipe_feed fs/splice.c:502 [inline] __splice_from_pipe+0x326/0x7a0 fs/splice.c:626 splice_from_pipe fs/splice.c:661 [inline] default_file_splice_write+0xc5/0x150 fs/splice.c:809 do_splice_from fs/splice.c:851 [inline] direct_splice_actor+0x115/0x160 fs/splice.c:1018 splice_direct_to_actor+0x27c/0x730 fs/splice.c:973 do_splice_direct+0x164/0x210 fs/splice.c:1061 do_sendfile+0x47f/0xb30 fs/read_write.c:1441 SYSC_sendfile64 fs/read_write.c:1502 [inline] SyS_sendfile64+0xff/0x110 fs/read_write.c:1488 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x7feb1803f0e9 RSP: 002b:00007feb169b4168 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007feb18151f60 RCX: 00007feb1803f0e9 RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000005 RBP: 00007feb1809908d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffe514d03af R14: 00007feb169b4300 R15: 0000000000022000 device bridge0 entered promiscuous mode syz-executor.1 (9580): drop_caches: 2 syz-executor.1 (9657): drop_caches: 2 syz-executor.1 (9667): drop_caches: 2 audit: type=1804 audit(1650376099.288:2): pid=9689 uid=0 auid=4294967295 ses=4294967295 op="invalid_pcr" cause="open_writers" comm="syz-executor.1" name="/root/syzkaller-testdir1339444586/syzkaller.8pI0Eo/7/bus/file0" dev="sda1" ino=13964 res=1 netlink: 24 bytes leftover after parsing attributes in process `syz-executor.4'. audit: type=1800 audit(1650376099.338:3): pid=9693 uid=0 auid=4294967295 ses=4294967295 op="collect_data" cause="failed(directio)" comm="syz-executor.5" name="bus" dev="sda1" ino=13905 res=0 netlink: 24 bytes leftover after parsing attributes in process `syz-executor.4'. EXT4-fs (loop5): Unrecognized mount option "9rc4+.{O"NzwF+[|y" or missing value print_req_error: I/O error, dev loop5, sector 0 Buffer I/O error on dev loop5, logical block 0, async page read print_req_error: I/O error, dev loop5, sector 4 Buffer I/O error on dev loop5, logical block 2, async page read print_req_error: I/O error, dev loop5, sector 6 Buffer I/O error on dev loop5, logical block 3, async page read netlink: 24 bytes leftover after parsing attributes in process `syz-executor.4'. audit: type=1800 audit(1650376100.138:4): pid=9726 uid=0 auid=4294967295 ses=4294967295 op="collect_data" cause="failed(directio)" comm="syz-executor.5" name="bus" dev="sda1" ino=13970 res=0 netlink: 24 bytes leftover after parsing attributes in process `syz-executor.4'. EXT4-fs (loop5): Unrecognized mount option "9rc4+.{O"NzwF+[|y" or missing value print_req_error: I/O error, dev loop5, sector 0 Buffer I/O error on dev loop5, logical block 0, async page read print_req_error: I/O error, dev loop5, sector 4 Buffer I/O error on dev loop5, logical block 2, async page read print_req_error: I/O error, dev loop5, sector 6 Buffer I/O error on dev loop5, logical block 3, async page read audit: type=1800 audit(1650376101.028:5): pid=9764 uid=0 auid=4294967295 ses=4294967295 op="collect_data" cause="failed(directio)" comm="syz-executor.5" name="bus" dev="sda1" ino=14013 res=0 EXT4-fs (loop5): Unrecognized mount option "9rc4+.{O"NzwF+[|y" or missing value netlink: 96 bytes leftover after parsing attributes in process `syz-executor.3'. audit: type=1800 audit(1650376101.618:6): pid=9835 uid=0 auid=4294967295 ses=4294967295 op="collect_data" cause="failed(directio)" comm="syz-executor.5" name="bus" dev="sda1" ino=13997 res=0 EXT4-fs (loop5): Unrecognized mount option "9rc4+.{O"NzwF+[|y" or missing value netlink: 96 bytes leftover after parsing attributes in process `syz-executor.3'. netlink: 96 bytes leftover after parsing attributes in process `syz-executor.3'. netlink: 96 bytes leftover after parsing attributes in process `syz-executor.3'. syz-executor.3 (9978) used greatest stack depth: 24080 bytes left 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