====================================================== WARNING: possible circular locking dependency detected 5.5.0-rc7-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.1/13379 is trying to acquire lock: ffff88808ddc7790 (&sb->s_type->i_mutex_key#13){+.+.}, at: inode_lock include/linux/fs.h:791 [inline] ffff88808ddc7790 (&sb->s_type->i_mutex_key#13){+.+.}, at: shmem_fallocate+0x15a/0xd40 mm/shmem.c:2736 but task is already holding lock: ffffffff89a40480 (fs_reclaim){+.+.}, at: fs_reclaim_acquire.part.0+0x0/0x30 include/linux/uaccess.h:173 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (fs_reclaim){+.+.}: __fs_reclaim_acquire mm/page_alloc.c:4073 [inline] fs_reclaim_acquire.part.0+0x24/0x30 mm/page_alloc.c:4084 fs_reclaim_acquire mm/page_alloc.c:4670 [inline] prepare_alloc_pages mm/page_alloc.c:4667 [inline] __alloc_pages_nodemask+0x52d/0x910 mm/page_alloc.c:4719 alloc_pages_vma+0xdd/0x620 mm/mempolicy.c:2174 shmem_alloc_page+0xc0/0x180 mm/shmem.c:1499 shmem_alloc_and_acct_page+0x165/0x990 mm/shmem.c:1524 shmem_getpage_gfp+0x56d/0x29a0 mm/shmem.c:1838 shmem_getpage mm/shmem.c:154 [inline] shmem_write_begin+0x105/0x1e0 mm/shmem.c:2488 generic_perform_write+0x23b/0x540 mm/filemap.c:3309 __generic_file_write_iter+0x25e/0x630 mm/filemap.c:3438 generic_file_write_iter+0x420/0x68e mm/filemap.c:3470 call_write_iter include/linux/fs.h:1902 [inline] new_sync_write+0x4d3/0x770 fs/read_write.c:483 __vfs_write+0xe1/0x110 fs/read_write.c:496 vfs_write+0x268/0x5d0 fs/read_write.c:558 ksys_write+0x14f/0x290 fs/read_write.c:611 __do_sys_write fs/read_write.c:623 [inline] __se_sys_write fs/read_write.c:620 [inline] __x64_sys_write+0x73/0xb0 fs/read_write.c:620 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #0 (&sb->s_type->i_mutex_key#13){+.+.}: check_prev_add kernel/locking/lockdep.c:2475 [inline] check_prevs_add kernel/locking/lockdep.c:2580 [inline] validate_chain kernel/locking/lockdep.c:2970 [inline] __lock_acquire+0x2596/0x4a00 kernel/locking/lockdep.c:3954 lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4484 down_write+0x93/0x150 kernel/locking/rwsem.c:1534 inode_lock include/linux/fs.h:791 [inline] shmem_fallocate+0x15a/0xd40 mm/shmem.c:2736 ashmem_shrink_scan drivers/staging/android/ashmem.c:462 [inline] ashmem_shrink_scan+0x370/0x510 drivers/staging/android/ashmem.c:437 do_shrink_slab+0x40f/0xad0 mm/vmscan.c:526 shrink_slab mm/vmscan.c:687 [inline] shrink_slab+0x19a/0x680 mm/vmscan.c:660 shrink_node_memcgs mm/vmscan.c:2687 [inline] shrink_node+0x46a/0x1ad0 mm/vmscan.c:2791 shrink_zones mm/vmscan.c:2996 [inline] do_try_to_free_pages+0x3ba/0x14f0 mm/vmscan.c:3049 try_to_free_pages+0x2dc/0x970 mm/vmscan.c:3288 __perform_reclaim mm/page_alloc.c:4113 [inline] __alloc_pages_direct_reclaim mm/page_alloc.c:4134 [inline] __alloc_pages_slowpath+0x97e/0x2900 mm/page_alloc.c:4537 __alloc_pages_nodemask+0x646/0x910 mm/page_alloc.c:4751 alloc_pages_current+0x107/0x210 mm/mempolicy.c:2211 alloc_pages include/linux/gfp.h:532 [inline] ion_page_pool_alloc_pages drivers/staging/android/ion/ion_page_pool.c:19 [inline] ion_page_pool_alloc+0x18c/0x280 drivers/staging/android/ion/ion_page_pool.c:78 alloc_buffer_page drivers/staging/android/ion/ion_system_heap.c:53 [inline] alloc_largest_available drivers/staging/android/ion/ion_system_heap.c:87 [inline] ion_system_heap_allocate+0x269/0xc20 drivers/staging/android/ion/ion_system_heap.c:118 ion_buffer_create drivers/staging/android/ion/ion.c:50 [inline] ion_alloc drivers/staging/android/ion/ion.c:383 [inline] ion_ioctl+0x3ba/0xd20 drivers/staging/android/ion/ion.c:509 vfs_ioctl fs/ioctl.c:47 [inline] file_ioctl fs/ioctl.c:545 [inline] do_vfs_ioctl+0x977/0x14e0 fs/ioctl.c:732 ksys_ioctl+0xab/0xd0 fs/ioctl.c:749 __do_sys_ioctl fs/ioctl.c:756 [inline] __se_sys_ioctl fs/ioctl.c:754 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:754 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(fs_reclaim); lock(&sb->s_type->i_mutex_key#13); lock(fs_reclaim); lock(&sb->s_type->i_mutex_key#13); *** DEADLOCK *** 3 locks held by syz-executor.1/13379: #0: ffff88821a87ceb8 (&idev->lock){++++}, at: ion_alloc drivers/staging/android/ion/ion.c:378 [inline] #0: ffff88821a87ceb8 (&idev->lock){++++}, at: ion_ioctl+0x216/0xd20 drivers/staging/android/ion/ion.c:509 #1: ffffffff89a40480 (fs_reclaim){+.+.}, at: fs_reclaim_acquire.part.0+0x0/0x30 include/linux/uaccess.h:173 #2: ffffffff89a1dfc8 (shrinker_rwsem){++++}, at: shrink_slab mm/vmscan.c:677 [inline] #2: ffffffff89a1dfc8 (shrinker_rwsem){++++}, at: shrink_slab+0xe6/0x680 mm/vmscan.c:660 stack backtrace: CPU: 1 PID: 13379 Comm: syz-executor.1 Not tainted 5.5.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x197/0x210 lib/dump_stack.c:118 print_circular_bug.isra.0.cold+0x163/0x172 kernel/locking/lockdep.c:1684 check_noncircular+0x32e/0x3e0 kernel/locking/lockdep.c:1808 check_prev_add kernel/locking/lockdep.c:2475 [inline] check_prevs_add kernel/locking/lockdep.c:2580 [inline] validate_chain kernel/locking/lockdep.c:2970 [inline] __lock_acquire+0x2596/0x4a00 kernel/locking/lockdep.c:3954 lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4484 down_write+0x93/0x150 kernel/locking/rwsem.c:1534 inode_lock include/linux/fs.h:791 [inline] shmem_fallocate+0x15a/0xd40 mm/shmem.c:2736 ashmem_shrink_scan drivers/staging/android/ashmem.c:462 [inline] ashmem_shrink_scan+0x370/0x510 drivers/staging/android/ashmem.c:437 do_shrink_slab+0x40f/0xad0 mm/vmscan.c:526 shrink_slab mm/vmscan.c:687 [inline] shrink_slab+0x19a/0x680 mm/vmscan.c:660 shrink_node_memcgs mm/vmscan.c:2687 [inline] shrink_node+0x46a/0x1ad0 mm/vmscan.c:2791 shrink_zones mm/vmscan.c:2996 [inline] do_try_to_free_pages+0x3ba/0x14f0 mm/vmscan.c:3049 try_to_free_pages+0x2dc/0x970 mm/vmscan.c:3288 __perform_reclaim mm/page_alloc.c:4113 [inline] __alloc_pages_direct_reclaim mm/page_alloc.c:4134 [inline] __alloc_pages_slowpath+0x97e/0x2900 mm/page_alloc.c:4537 __alloc_pages_nodemask+0x646/0x910 mm/page_alloc.c:4751 alloc_pages_current+0x107/0x210 mm/mempolicy.c:2211 alloc_pages include/linux/gfp.h:532 [inline] ion_page_pool_alloc_pages drivers/staging/android/ion/ion_page_pool.c:19 [inline] ion_page_pool_alloc+0x18c/0x280 drivers/staging/android/ion/ion_page_pool.c:78 alloc_buffer_page drivers/staging/android/ion/ion_system_heap.c:53 [inline] alloc_largest_available drivers/staging/android/ion/ion_system_heap.c:87 [inline] ion_system_heap_allocate+0x269/0xc20 drivers/staging/android/ion/ion_system_heap.c:118 ion_buffer_create drivers/staging/android/ion/ion.c:50 [inline] ion_alloc drivers/staging/android/ion/ion.c:383 [inline] ion_ioctl+0x3ba/0xd20 drivers/staging/android/ion/ion.c:509 vfs_ioctl fs/ioctl.c:47 [inline] file_ioctl fs/ioctl.c:545 [inline] do_vfs_ioctl+0x977/0x14e0 fs/ioctl.c:732 ksys_ioctl+0xab/0xd0 fs/ioctl.c:749 __do_sys_ioctl fs/ioctl.c:756 [inline] __se_sys_ioctl fs/ioctl.c:754 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:754 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45b349 Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fa5d6973c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fa5d69746d4 RCX: 000000000045b349 RDX: 00000000200001c0 RSI: 00000000c0184900 RDI: 0000000000000003 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000343 R14: 00000000004c4692 R15: 000000000075bf2c