====================================================== [ INFO: possible circular locking dependency detected ] 4.9.203-syzkaller #0 Not tainted ------------------------------------------------------- syz-executor.5/9473 is trying to acquire lock: (&mm->mmap_sem){++++++}, at: [<00000000425d2fce>] __do_page_fault+0x7bd/0xa60 arch/x86/mm/fault.c:1337 but task is already holding lock: (&sb->s_type->i_mutex_key#10){+.+.+.}, at: [<0000000037918163>] inode_lock include/linux/fs.h:771 [inline] (&sb->s_type->i_mutex_key#10){+.+.+.}, at: [<0000000037918163>] generic_file_write_iter+0x9a/0x630 mm/filemap.c:3090 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: lock_acquire+0x133/0x3d0 kernel/locking/lockdep.c:3759 down_write+0x41/0xa0 kernel/locking/rwsem.c:52 inode_lock include/linux/fs.h:771 [inline] shmem_fallocate+0x143/0xab0 mm/shmem.c:2683 ashmem_shrink_scan drivers/staging/android/ashmem.c:462 [inline] ashmem_shrink_scan+0x1c3/0x4c0 drivers/staging/android/ashmem.c:446 ashmem_ioctl+0x29b/0xdd0 drivers/staging/android/ashmem.c:804 vfs_ioctl fs/ioctl.c:43 [inline] file_ioctl fs/ioctl.c:493 [inline] do_vfs_ioctl+0xb87/0x11d0 fs/ioctl.c:677 SYSC_ioctl fs/ioctl.c:694 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:685 do_syscall_64+0x1ad/0x5c0 arch/x86/entry/common.c:288 entry_SYSCALL_64_after_swapgs+0x5d/0xdb lock_acquire+0x133/0x3d0 kernel/locking/lockdep.c:3759 __mutex_lock_common kernel/locking/mutex.c:521 [inline] mutex_lock_nested+0xc7/0x920 kernel/locking/mutex.c:621 ashmem_mmap+0x53/0x470 drivers/staging/android/ashmem.c:378 mmap_region+0x7e7/0xfa0 mm/mmap.c:1726 do_mmap+0x539/0xbc0 mm/mmap.c:1505 do_mmap_pgoff include/linux/mm.h:2066 [inline] vm_mmap_pgoff+0x179/0x1c0 mm/util.c:329 SYSC_mmap_pgoff mm/mmap.c:1555 [inline] SyS_mmap_pgoff+0xfa/0x1b0 mm/mmap.c:1513 SYSC_mmap arch/x86/kernel/sys_x86_64.c:96 [inline] SyS_mmap+0x16/0x20 arch/x86/kernel/sys_x86_64.c:87 do_syscall_64+0x1ad/0x5c0 arch/x86/entry/common.c:288 entry_SYSCALL_64_after_swapgs+0x5d/0xdb check_prev_add kernel/locking/lockdep.c:1828 [inline] check_prevs_add kernel/locking/lockdep.c:1938 [inline] validate_chain kernel/locking/lockdep.c:2265 [inline] __lock_acquire+0x2d22/0x4390 kernel/locking/lockdep.c:3345 lock_acquire+0x133/0x3d0 kernel/locking/lockdep.c:3759 down_read+0x44/0xb0 kernel/locking/rwsem.c:22 __do_page_fault+0x7bd/0xa60 arch/x86/mm/fault.c:1337 do_page_fault+0x28/0x30 arch/x86/mm/fault.c:1464 page_fault+0x25/0x30 arch/x86/entry/entry_64.S:956 generic_perform_write+0x1b6/0x500 mm/filemap.c:2930 __generic_file_write_iter+0x340/0x530 mm/filemap.c:3065 generic_file_write_iter+0x38a/0x630 mm/filemap.c:3093 new_sync_write fs/read_write.c:498 [inline] __vfs_write+0x3c1/0x560 fs/read_write.c:511 vfs_write+0x185/0x520 fs/read_write.c:559 SYSC_pwrite64 fs/read_write.c:649 [inline] SyS_pwrite64+0x13f/0x170 fs/read_write.c:636 do_syscall_64+0x1ad/0x5c0 arch/x86/entry/common.c:288 entry_SYSCALL_64_after_swapgs+0x5d/0xdb other info that might help us debug this: Chain exists of: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&sb->s_type->i_mutex_key#10); lock(ashmem_mutex); lock(&sb->s_type->i_mutex_key#10); lock(&mm->mmap_sem); *** DEADLOCK *** 2 locks held by syz-executor.5/9473: #0: (sb_writers#6){.+.+.+}, at: [<000000004cc4cf52>] file_start_write include/linux/fs.h:2645 [inline] #0: (sb_writers#6){.+.+.+}, at: [<000000004cc4cf52>] vfs_write+0x3e9/0x520 fs/read_write.c:558 #1: (&sb->s_type->i_mutex_key#10){+.+.+.}, at: [<0000000037918163>] inode_lock include/linux/fs.h:771 [inline] #1: (&sb->s_type->i_mutex_key#10){+.+.+.}, at: [<0000000037918163>] generic_file_write_iter+0x9a/0x630 mm/filemap.c:3090 stack backtrace: CPU: 0 PID: 9473 Comm: syz-executor.5 Not tainted 4.9.203-syzkaller #0 ffff8801a9aa75e8 ffffffff81b55f6b ffffffff83caeb80 ffffffff83cb8000 ffffffff83cd6960 ffffffff8424ff40 ffff8801c98a17c0 ffff8801a9aa7640 ffffffff81406eaa dffffc0000000000 ffffffff840866c0 ffff8801c98a20c0 Call Trace: [<00000000c8dc72c5>] __dump_stack lib/dump_stack.c:15 [inline] [<00000000c8dc72c5>] dump_stack+0xcb/0x130 lib/dump_stack.c:56 [<0000000024e7c7a2>] print_circular_bug.cold+0x2f6/0x454 kernel/locking/lockdep.c:1202 [<0000000014f23b2c>] check_prev_add kernel/locking/lockdep.c:1828 [inline] [<0000000014f23b2c>] check_prevs_add kernel/locking/lockdep.c:1938 [inline] [<0000000014f23b2c>] validate_chain kernel/locking/lockdep.c:2265 [inline] [<0000000014f23b2c>] __lock_acquire+0x2d22/0x4390 kernel/locking/lockdep.c:3345 [<000000002bbf162f>] lock_acquire+0x133/0x3d0 kernel/locking/lockdep.c:3759 [<000000007959c9a5>] down_read+0x44/0xb0 kernel/locking/rwsem.c:22 [<00000000425d2fce>] __do_page_fault+0x7bd/0xa60 arch/x86/mm/fault.c:1337 [<0000000059101a31>] do_page_fault+0x28/0x30 arch/x86/mm/fault.c:1464 [<000000007643f665>] page_fault+0x25/0x30 arch/x86/entry/entry_64.S:956 [<00000000031f069c>] generic_perform_write+0x1b6/0x500 mm/filemap.c:2930 [<00000000f5094a0b>] __generic_file_write_iter+0x340/0x530 mm/filemap.c:3065 [<00000000a22e10b7>] generic_file_write_iter+0x38a/0x630 mm/filemap.c:3093 [<000000007ddc6e4f>] new_sync_write fs/read_write.c:498 [inline] [<000000007ddc6e4f>] __vfs_write+0x3c1/0x560 fs/read_write.c:511 [<000000003626fba9>] vfs_write+0x185/0x520 fs/read_write.c:559 [<00000000b4aa449e>] SYSC_pwrite64 fs/read_write.c:649 [inline] [<00000000b4aa449e>] SyS_pwrite64+0x13f/0x170 fs/read_write.c:636 [<00000000242b2b66>] do_syscall_64+0x1ad/0x5c0 arch/x86/entry/common.c:288 [<00000000dd10eec5>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb audit_printk_skb: 48 callbacks suppressed audit: type=1400 audit(1574925075.385:3617): avc: denied { create } for pid=9494 comm="syz-executor.3" 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 audit: type=1400 audit(1574925075.445:3618): avc: denied { write } for pid=9494 comm="syz-executor.3" 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 audit: type=1400 audit(1574925075.575:3619): avc: denied { mac_admin } for pid=9493 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 audit: type=1400 audit(1574925075.625:3620): avc: denied { create } for pid=9494 comm="syz-executor.3" 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 audit: type=1400 audit(1574925075.635:3621): avc: denied { write } for pid=9494 comm="syz-executor.3" 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 audit: type=1400 audit(1574925075.775:3622): avc: denied { read } for pid=9494 comm="syz-executor.3" 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 audit: type=1400 audit(1574925075.865:3623): avc: denied { read } for pid=9494 comm="syz-executor.3" 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 audit: type=1400 audit(1574925076.165:3624): avc: denied { create } for pid=9494 comm="syz-executor.3" 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 audit: type=1400 audit(1574925076.165:3625): avc: denied { write } for pid=9494 comm="syz-executor.3" 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 audit: type=1400 audit(1574925076.175:3626): avc: denied { create } for pid=9494 comm="syz-executor.3" 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: Context 0006ce58 000001bf 00000001 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 0006c83b 00000000 00000002 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 is not valid (left unmapped). audit_printk_skb: 18 callbacks suppressed audit: type=1400 audit(1574925082.495:3633): avc: denied { mac_admin } for pid=9762 comm="syz-executor.1" 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 0006ce5b 000001bf 00000001 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 0006c843 00000000 00000002 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 is not valid (left unmapped). audit: type=1400 audit(1574925082.705:3634): avc: denied { create } for pid=9767 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(1574925082.795:3635): avc: denied { mac_admin } for pid=9767 comm="syz-executor.0" 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 0006ce5b 000001bf 00000001 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 0006c848 00000000 00000002 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 is not valid (left unmapped). audit: type=1400 audit(1574925082.905:3636): avc: denied { create } for pid=9769 comm="syz-executor.3" 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 audit: type=1400 audit(1574925082.915:3637): avc: denied { write } for pid=9769 comm="syz-executor.3" 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 audit: type=1400 audit(1574925082.935:3638): avc: denied { mac_admin } for pid=9766 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 audit: type=1400 audit(1574925082.985:3639): avc: denied { create } for pid=9770 comm="syz-executor.5" 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 audit: type=1400 audit(1574925083.025:3640): avc: denied { write } for pid=9770 comm="syz-executor.5" 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 audit: type=1400 audit(1574925083.095:3641): avc: denied { read } for pid=9769 comm="syz-executor.3" 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 audit: type=1400 audit(1574925083.195:3642): avc: denied { read } for pid=9770 comm="syz-executor.5" 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 netlink: 4 bytes leftover after parsing attributes in process `syz-executor.0'. netlink: 4 bytes leftover after parsing attributes in process `syz-executor.0'. netlink: 4 bytes leftover after parsing attributes in process `syz-executor.0'. SELinux: Context 0006ce61 000001bf 00000001 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 0006c84e 00000000 00000002 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 is not valid (left unmapped). SELinux: Context 0006ce62 000001bf 00000001 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 0006c84e 00000000 00000002 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 is not valid (left unmapped).