====================================================== [ INFO: possible circular locking dependency detected ] 4.9.203-syzkaller #0 Not tainted ------------------------------------------------------- syz-executor.5/16825 is trying to acquire lock: (&mm->mmap_sem){++++++}, at: [<000000000ef965c7>] __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: [<00000000f98f3b62>] inode_lock include/linux/fs.h:771 [inline] (&sb->s_type->i_mutex_key#10){+.+.+.}, at: [<00000000f98f3b62>] 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.5/16825: #0: (sb_writers#6){.+.+.+}, at: [<00000000e4f11350>] file_start_write include/linux/fs.h:2645 [inline] #0: (sb_writers#6){.+.+.+}, at: [<00000000e4f11350>] vfs_write+0x3e9/0x520 fs/read_write.c:558 #1: (&sb->s_type->i_mutex_key#10){+.+.+.}, at: [<00000000f98f3b62>] inode_lock include/linux/fs.h:771 [inline] #1: (&sb->s_type->i_mutex_key#10){+.+.+.}, at: [<00000000f98f3b62>] generic_file_write_iter+0x9a/0x630 mm/filemap.c:3090 stack backtrace: CPU: 0 PID: 16825 Comm: syz-executor.5 Not tainted 4.9.203-syzkaller #0 ffff8801d524f5e8 ffffffff81b55f6b ffffffff83caf090 ffffffff83cb8000 ffffffff83ce75b0 ffffffff8424ff40 ffff8801a2134740 ffff8801d524f640 ffffffff81406eaa dffffc0000000000 ffffffff84076f40 ffff8801a2135040 Call Trace: [<0000000046bb0357>] __dump_stack lib/dump_stack.c:15 [inline] [<0000000046bb0357>] dump_stack+0xcb/0x130 lib/dump_stack.c:56 [<000000008029ca81>] print_circular_bug.cold+0x2f6/0x454 kernel/locking/lockdep.c:1202 [<00000000f72ff162>] check_prev_add kernel/locking/lockdep.c:1828 [inline] [<00000000f72ff162>] check_prevs_add kernel/locking/lockdep.c:1938 [inline] [<00000000f72ff162>] validate_chain kernel/locking/lockdep.c:2265 [inline] [<00000000f72ff162>] __lock_acquire+0x2d22/0x4390 kernel/locking/lockdep.c:3345 [<00000000a933f3b1>] lock_acquire+0x133/0x3d0 kernel/locking/lockdep.c:3759 [<000000003ae59e9f>] down_read+0x44/0xb0 kernel/locking/rwsem.c:22 [<000000000ef965c7>] __do_page_fault+0x7bd/0xa60 arch/x86/mm/fault.c:1337 [<0000000076314110>] do_page_fault+0x28/0x30 arch/x86/mm/fault.c:1464 [<00000000da1322e5>] page_fault+0x25/0x30 arch/x86/entry/entry_64.S:956 [<000000003bf17a55>] generic_perform_write+0x1b6/0x500 mm/filemap.c:2930 [<0000000029ac3350>] __generic_file_write_iter+0x340/0x530 mm/filemap.c:3065 [<00000000e904e356>] generic_file_write_iter+0x38a/0x630 mm/filemap.c:3093 [<0000000091af96f5>] new_sync_write fs/read_write.c:498 [inline] [<0000000091af96f5>] __vfs_write+0x3c1/0x560 fs/read_write.c:511 [<000000001992206a>] vfs_write+0x185/0x520 fs/read_write.c:559 [<00000000fdc9a9d3>] SYSC_pwrite64 fs/read_write.c:649 [inline] [<00000000fdc9a9d3>] SyS_pwrite64+0x13f/0x170 fs/read_write.c:636 [<0000000046b6c700>] do_syscall_64+0x1ad/0x5c0 arch/x86/entry/common.c:288 [<000000007fcca7ff>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb audit: type=1400 audit(2000000199.560:4790): avc: denied { create } for pid=16847 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_generic_socket permissive=1 loop2: p1 p2[EZD] p3 p4 loop2: p1 start 1 is beyond EOD, truncated loop2: p2 size 1073741824 extends beyond EOD, truncated loop2: p3 size 1912633224 extends beyond EOD, truncated loop2: p4 size 32768 extends beyond EOD, truncated audit: type=1400 audit(2000000200.040:4791): avc: denied { write } for pid=16847 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_generic_socket permissive=1 audit: type=1400 audit(2000000200.330:4792): avc: denied { create } for pid=16847 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_generic_socket permissive=1 audit: type=1400 audit(2000000200.420:4793): avc: denied { write } for pid=16847 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_generic_socket permissive=1 audit: type=1400 audit(2000000201.250:4794): avc: denied { setattr } for pid=16890 comm="syz-executor.2" name="smaps" dev="proc" ino=120831 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=file permissive=1 loop0: p1 p2[EZD] p3 p4 loop0: p1 start 1 is beyond EOD, truncated loop0: p2 size 1073741824 extends beyond EOD, truncated loop0: p3 size 1912633224 extends beyond EOD, truncated loop0: p4 size 32768 extends beyond EOD, truncated audit: type=1400 audit(2000000201.730:4795): avc: denied { setattr } for pid=16890 comm="syz-executor.2" name="smaps" dev="proc" ino=120831 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=file permissive=1 loop0: p1 p2[EZD] p3 p4 loop0: p1 start 1 is beyond EOD, truncated loop0: p2 size 1073741824 extends beyond EOD, truncated loop0: p3 size 1912633224 extends beyond EOD, truncated loop0: p4 size 32768 extends beyond EOD, truncated loop2: p1 p2[EZD] p3 p4 loop2: p1 start 1 is beyond EOD, truncated loop2: p2 size 1073741824 extends beyond EOD, truncated loop2: p3 size 1912633224 extends beyond EOD, truncated loop2: p4 size 32768 extends beyond EOD, truncated loop0: p1 p2[EZD] p3 p4 loop0: p1 start 1 is beyond EOD, truncated loop0: p2 size 1073741824 extends beyond EOD, truncated loop0: p3 size 1912633224 extends beyond EOD, truncated loop0: p4 size 32768 extends beyond EOD, truncated loop0: p1 p2[EZD] p3 p4 loop0: p2 size 1073741824 extends beyond EOD, truncated loop0: p3 size 1912633224 extends beyond EOD, truncated audit: type=1400 audit(2000000204.470:4796): avc: denied { create } for pid=17001 comm="syz-executor.2" 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 loop2: p1 p2[EZD] p3 p4 loop2: p1 start 1 is beyond EOD, truncated loop2: p2 size 1073741824 extends beyond EOD, truncated loop2: p3 size 1912633224 extends beyond EOD, truncated loop2: p4 size 32768 extends beyond EOD, truncated audit: type=1400 audit(2000000205.130:4797): avc: denied { write } for pid=17001 comm="syz-executor.2" 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(2000000205.130:4798): avc: denied { create } for pid=17001 comm="syz-executor.2" 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(2000000205.130:4799): avc: denied { write } for pid=17001 comm="syz-executor.2" 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 loop2: p1 p2[EZD] p3 p4 loop2: p2 size 1073741824 extends beyond EOD, truncated loop2: p3 size 1912633224 extends beyond EOD, truncated loop0: p1 p2[EZD] p3 p4 loop0: p1 start 1 is beyond EOD, [ 1495.358297] loop2: p1 p2[EZD] p3 p4 loop2: p1 start 1 is beyond EOD, truncated loop2: p2 size 1073741824 extends beyond EOD, truncated loop2: p3 size 1912633224 extends beyond EOD, truncated loop2: p4 size 32768 extends beyond EOD, truncated truncated loop0: p2 size 1073741824 extends beyond EOD, truncated loop0: p3 size 1912633224 extends beyond EOD, truncated loop0: p4 size 32768 extends beyond EOD, truncated loop2: p1 p2[EZD] p3 p4 loop2: p1 start 1 is beyond EOD, truncated loop2: p2 size 1073741824 extends beyond EOD, truncated