bisecting fixing commit since f5b7769eb0400ec5217a47e41148a9f816ca1f9f building syzkaller on 27c5f59f504f562333e3cd5e715fea5cb69c396e testing commit f5b7769eb0400ec5217a47e41148a9f816ca1f9f with gcc (GCC) 8.1.0 kernel signature: fe9bc77624556fce10ff8d69ad7eaed311815db1 all runs: crashed: KASAN: use-after-free Read in blkdev_get testing current HEAD eea2d5da29e396b6cc1fb35e36bcbf5f57731015 testing commit eea2d5da29e396b6cc1fb35e36bcbf5f57731015 with gcc (GCC) 8.1.0 kernel signature: 6cc766e597c906223751d8dde47d396db3260936 all runs: crashed: KASAN: use-after-free Read in blkdev_get revisions tested: 2, total time: 24m33.462228115s (build: 10m27.046190106s, test: 13m21.113083952s) the crash still happens on HEAD commit msg: Merge tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm crash: KASAN: use-after-free Read in blkdev_get REISERFS (device loop0): using ordered data mode REISERFS (device loop2): found reiserfs format "3.5" with non-standard journal reiserfs: using flush barriers ================================================================== REISERFS (device loop3): found reiserfs format "3.5" with non-standard journal BUG: KASAN: use-after-free in __mutex_lock_common kernel/locking/mutex.c:941 [inline] BUG: KASAN: use-after-free in __mutex_lock+0x10cc/0x1400 kernel/locking/mutex.c:1106 Read of size 8 at addr ffff8881ce3981f0 by task syz-executor4/31878 CPU: 0 PID: 31878 Comm: syz-executor4 Not tainted 5.4.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 REISERFS (device loop2): using ordered data mode Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x12f/0x187 lib/dump_stack.c:118 reiserfs: using flush barriers print_address_description.constprop.8+0x3b/0x60 mm/kasan/report.c:374 REISERFS (device loop3): using ordered data mode __kasan_report.cold.11+0x1b/0x39 mm/kasan/report.c:506 kasan_report+0x12/0x20 mm/kasan/common.c:639 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135 __mutex_lock_common kernel/locking/mutex.c:941 [inline] __mutex_lock+0x10cc/0x1400 kernel/locking/mutex.c:1106 reiserfs: using flush barriers mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1121 blkdev_get+0xb2/0x230 fs/block_dev.c:1742 blkdev_get_by_dev+0x31/0x50 fs/block_dev.c:1839 journal_init_dev fs/reiserfs/journal.c:2619 [inline] journal_init+0xa28/0x6730 fs/reiserfs/journal.c:2766 reiserfs_fill_super+0x96b/0x28b0 fs/reiserfs/super.c:2031 mount_bdev+0x27b/0x340 fs/super.c:1415 get_super_block+0x10/0x20 fs/reiserfs/super.c:2604 legacy_get_tree+0x103/0x1f0 fs/fs_context.c:647 vfs_get_tree+0x8b/0x2d0 fs/super.c:1545 do_new_mount fs/namespace.c:2822 [inline] do_mount+0x1285/0x1b70 fs/namespace.c:3142 ksys_mount+0xba/0xe0 fs/namespace.c:3351 __do_sys_mount fs/namespace.c:3365 [inline] __se_sys_mount fs/namespace.c:3362 [inline] __x64_sys_mount+0xb9/0x150 fs/namespace.c:3362 do_syscall_64+0xd0/0x600 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4586aa Code: b8 a6 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 dd 8f fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 ba 8f fb ff c3 66 0f 1f 84 00 00 00 00 00 RSP: 002b:00007f657d1c4a88 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 0000000020000228 RCX: 00000000004586aa RDX: 00007f657d1c4ad0 RSI: 0000000020000100 RDI: 00007f657d1c4af0 RBP: 0000000000000001 R08: 00007f657d1c4b30 R09: 00007f657d1c4ad0 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003 R13: 0000000000000001 R14: 00000000004d2f98 R15: 0000000000000000 Allocated by task 31878: save_stack+0x21/0x90 mm/kasan/common.c:72 set_track mm/kasan/common.c:80 [inline] __kasan_kmalloc.constprop.7+0xc1/0xd0 mm/kasan/common.c:513 kasan_slab_alloc+0x12/0x20 mm/kasan/common.c:521 slab_post_alloc_hook mm/slab.h:584 [inline] slab_alloc mm/slab.c:3320 [inline] kmem_cache_alloc+0x121/0x740 mm/slab.c:3484 bdev_alloc_inode+0x15/0x30 fs/block_dev.c:772 alloc_inode+0x5f/0x1a0 fs/inode.c:230 iget5_locked+0x103/0x190 fs/inode.c:1139 bdget+0x90/0x4e0 fs/block_dev.c:905 blkdev_get_by_dev+0x1b/0x50 fs/block_dev.c:1835 journal_init_dev fs/reiserfs/journal.c:2619 [inline] journal_init+0xa28/0x6730 fs/reiserfs/journal.c:2766 reiserfs_fill_super+0x96b/0x28b0 fs/reiserfs/super.c:2031 mount_bdev+0x27b/0x340 fs/super.c:1415 get_super_block+0x10/0x20 fs/reiserfs/super.c:2604 legacy_get_tree+0x103/0x1f0 fs/fs_context.c:647 vfs_get_tree+0x8b/0x2d0 fs/super.c:1545 do_new_mount fs/namespace.c:2822 [inline] do_mount+0x1285/0x1b70 fs/namespace.c:3142 ksys_mount+0xba/0xe0 fs/namespace.c:3351 __do_sys_mount fs/namespace.c:3365 [inline] __se_sys_mount fs/namespace.c:3362 [inline] __x64_sys_mount+0xb9/0x150 fs/namespace.c:3362 do_syscall_64+0xd0/0x600 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 31891: save_stack+0x21/0x90 mm/kasan/common.c:72 set_track mm/kasan/common.c:80 [inline] kasan_set_free_info mm/kasan/common.c:335 [inline] __kasan_slab_free+0x11a/0x170 mm/kasan/common.c:474 kasan_slab_free+0xe/0x10 mm/kasan/common.c:483 __cache_free mm/slab.c:3426 [inline] kmem_cache_free+0x86/0x2e0 mm/slab.c:3694 bdev_free_inode+0x17/0x20 fs/block_dev.c:780 i_callback+0x3f/0x70 fs/inode.c:219 __rcu_reclaim kernel/rcu/rcu.h:222 [inline] rcu_do_batch kernel/rcu/tree.c:2183 [inline] rcu_core+0x529/0x1390 kernel/rcu/tree.c:2408 rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2417 __do_softirq+0x248/0x94c kernel/softirq.c:292 The buggy address belongs to the object at ffff8881ce398180 which belongs to the cache bdev_cache(97:syz4) of size 1352 The buggy address is located 112 bytes inside of 1352-byte region [ffff8881ce398180, ffff8881ce3986c8) The buggy address belongs to the page: page:ffffea000738e600 refcount:1 mapcount:0 mapping:ffff8881c186e700 index:0xffff8881ce398ffe raw: 02fffc0000000200 ffffea0006da4008 ffffea0006ce7048 ffff8881c186e700 raw: ffff8881ce398ffe ffff8881ce398180 0000000100000002 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8881ce398080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8881ce398100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8881ce398180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881ce398200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881ce398280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================