================================================================== BUG: KASAN: use-after-free in disk_unblock_events+0x55/0x60 block/genhd.c:1543 Read of size 8 at addr ffff8800b67d40e8 by task syz-executor936/2128 CPU: 1 PID: 2128 Comm: syz-executor936 Not tainted 4.4.174+ #17 0000000000000000 826393fae749addf ffff8801d3f8f6c0 ffffffff81aad1a1 0000000000000000 ffffea0002d9f400 ffff8800b67d40e8 0000000000000008 0000000000000000 ffff8801d3f8f6f8 ffffffff81490120 0000000000000000 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x120 lib/dump_stack.c:51 [] print_address_description+0x6f/0x21b mm/kasan/report.c:252 [] kasan_report_error mm/kasan/report.c:351 [inline] [] kasan_report mm/kasan/report.c:408 [inline] [] kasan_report.cold+0x8c/0x2be mm/kasan/report.c:393 [] __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:429 [] disk_unblock_events+0x55/0x60 block/genhd.c:1543 [] __blkdev_get+0x70c/0xdf0 fs/block_dev.c:1297 [] blkdev_get+0x2e8/0x920 fs/block_dev.c:1353 [] blkdev_open+0x1aa/0x250 fs/block_dev.c:1508 [] do_dentry_open+0x38f/0xbd0 fs/open.c:749 [] vfs_open+0x10b/0x210 fs/open.c:862 [] do_last fs/namei.c:3269 [inline] [] path_openat+0x136f/0x4470 fs/namei.c:3406 [] do_filp_open+0x1a1/0x270 fs/namei.c:3440 [] do_sys_open+0x2f8/0x600 fs/open.c:1038 [] C_SYSC_open fs/compat.c:1092 [inline] [] compat_SyS_open+0x2a/0x40 fs/compat.c:1090 [] do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline] [] do_fast_syscall_32+0x32d/0xa90 arch/x86/entry/common.c:397 [] sysenter_flags_fixed+0xd/0x1a Allocated by task 2128: [] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63 [] save_stack mm/kasan/kasan.c:512 [inline] [] set_track mm/kasan/kasan.c:524 [inline] [] kasan_kmalloc.part.0+0x62/0xf0 mm/kasan/kasan.c:616 [] kasan_kmalloc+0xb7/0xd0 mm/kasan/kasan.c:601 [] kmem_cache_alloc_trace+0x123/0x2d0 mm/slub.c:2642 [] kmem_cache_alloc_node_trace include/linux/slab.h:367 [inline] [] kmalloc_node include/linux/slab.h:514 [inline] [] kzalloc_node include/linux/slab.h:631 [inline] [] alloc_disk_node+0x50/0x3c0 block/genhd.c:1282 [] alloc_disk+0x1b/0x20 block/genhd.c:1274 [] loop_add+0x380/0x830 drivers/block/loop.c:1857 [] loop_control_ioctl+0x138/0x2f0 drivers/block/loop.c:1988 [] C_SYSC_ioctl fs/compat_ioctl.c:1592 [inline] [] compat_SyS_ioctl+0x403/0x2210 fs/compat_ioctl.c:1544 [] do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline] [] do_fast_syscall_32+0x32d/0xa90 arch/x86/entry/common.c:397 [] sysenter_flags_fixed+0xd/0x1a Freed by task 2128: [] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63 [] save_stack mm/kasan/kasan.c:512 [inline] [] set_track mm/kasan/kasan.c:524 [inline] [] kasan_slab_free+0xb0/0x190 mm/kasan/kasan.c:589 [] slab_free_hook mm/slub.c:1383 [inline] [] slab_free_freelist_hook mm/slub.c:1405 [inline] [] slab_free mm/slub.c:2859 [inline] [] kfree+0xf4/0x310 mm/slub.c:3749 [] disk_release+0x255/0x330 block/genhd.c:1118 [] device_release+0x7d/0x220 drivers/base/core.c:247 [] kobject_cleanup lib/kobject.c:643 [inline] [] kobject_release lib/kobject.c:672 [inline] [] kref_sub include/linux/kref.h:73 [inline] [] kref_put include/linux/kref.h:98 [inline] [] kobject_put+0x14c/0x260 lib/kobject.c:689 [] put_disk+0x23/0x30 block/genhd.c:1346 [] __blkdev_get+0x66c/0xdf0 fs/block_dev.c:1290 [] blkdev_get+0x2e8/0x920 fs/block_dev.c:1353 [] blkdev_open+0x1aa/0x250 fs/block_dev.c:1508 [] do_dentry_open+0x38f/0xbd0 fs/open.c:749 [] vfs_open+0x10b/0x210 fs/open.c:862 [] do_last fs/namei.c:3269 [inline] [] path_openat+0x136f/0x4470 fs/namei.c:3406 [] do_filp_open+0x1a1/0x270 fs/namei.c:3440 [] do_sys_open+0x2f8/0x600 fs/open.c:1038 [] C_SYSC_open fs/compat.c:1092 [inline] [] compat_SyS_open+0x2a/0x40 fs/compat.c:1090 [] do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline] [] do_fast_syscall_32+0x32d/0xa90 arch/x86/entry/common.c:397 [] sysenter_flags_fixed+0xd/0x1a The buggy address belongs to the object at ffff8800b67d3b80 which belongs to the cache kmalloc-2048 of size 2048 The buggy address is located 1384 bytes inside of 2048-byte region [ffff8800b67d3b80, ffff8800b67d4380) The buggy address belongs to the page: BUG: unable to handle kernel NULL pointer dereference at 00000000000000a6 IP: [] get_freepointer mm/slub.c:237 [inline] IP: [] get_freepointer_safe mm/slub.c:252 [inline] IP: [] slab_alloc_node mm/slub.c:2584 [inline] IP: [] slab_alloc mm/slub.c:2623 [inline] IP: [] kmem_cache_alloc+0x9c/0x2c0 mm/slub.c:2628 PGD b73c4067 PUD b73c5067 PMD 0 Oops: 0000 [#1] PREEMPT SMP KASAN Modules linked in: CPU: 0 PID: 2099 Comm: syz-executor936 Not tainted 4.4.174+ #17 task: ffff8801d4114740 task.stack: ffff8800b6618000 RIP: 0010:[] [] get_freepointer mm/slub.c:237 [inline] RIP: 0010:[] [] get_freepointer_safe mm/slub.c:252 [inline] RIP: 0010:[] [] slab_alloc_node mm/slub.c:2584 [inline] RIP: 0010:[] [] slab_alloc mm/slub.c:2623 [inline] RIP: 0010:[] [] kmem_cache_alloc+0x9c/0x2c0 mm/slub.c:2628 RSP: 0018:ffff8800b661fb20 EFLAGS: 00010246 RAX: 00000000000000a6 RBX: ffff8801d42410f0 RCX: 0000000000022650 RDX: 0000000000061180 RSI: 0000000000061180 RDI: 0000000000022650 RBP: ffff8800b661fb50 R08: ffff8801d6a35ee0 R09: ffff8801d4115050 R10: ffffffff81456699 R11: 0000000000000000 R12: ffff8801da402dc0 R13: 00000000024000c0 R14: ffffffff8145677e R15: 00000000000000a6 FS: 0000000000000000(0000) GS:ffff8801db600000(0063) knlGS:0000000008d4a840 CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 CR2: 00000000000000a6 CR3: 00000000b6d2a000 CR4: 00000000001606b0 Stack: ffff8800b7e6b2a0 ffff8801d42410f0 ffff8800b67d4380 0000000000000000 ffff8801d4241178 ffff8800b67d4408 ffff8800b661fba0 ffffffff8145677e ffff8800b661fba0 ffff8801d6a35ee0 ffff8801d6a35f70 ffff8800b67d4380 Call Trace: [] anon_vma_chain_alloc mm/rmap.c:124 [inline] [] anon_vma_fork+0x1ce/0x4b0 mm/rmap.c:340 [] dup_mmap kernel/fork.c:471 [inline] [] dup_mm kernel/fork.c:985 [inline] [] copy_mm kernel/fork.c:1039 [inline] [] copy_process+0x412c/0x68a0 kernel/fork.c:1519 [] _do_fork+0x14e/0xdc0 kernel/fork.c:1806 [] SYSC_clone kernel/fork.c:1917 [inline] [] SyS_clone+0x37/0x50 kernel/fork.c:1911 [] do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline] [] do_fast_syscall_32+0x32d/0xa90 arch/x86/entry/common.c:397 [] sysenter_flags_fixed+0xd/0x1a Code: 48 8b 70 08 48 39 f2 75 e7 4c 8b 38 4d 85 ff 0f 84 80 01 00 00 49 63 44 24 20 49 8b 3c 24 4c 01 f8 40 f6 c7 0f 0f 85 a5 01 00 00 <48> 8b 18 48 8d 4a 08 4c 89 f8 65 48 0f c7 0f 0f 94 c0 84 c0 74 RIP [] slab_alloc_node mm/slub.c:2600 [inline] RIP [] slab_alloc mm/slub.c:2623 [inline] RIP [] kmem_cache_alloc+0x9c/0x2c0 mm/slub.c:2628 RSP CR2: 00000000000000a6 kasan: CONFIG_KASAN_INLINE enabled kasan: GPF could be caused by NULL-ptr deref or user memory accessgeneral protection fault: 0000 [#2] PREEMPT SMP KASAN Modules linked in: CPU: 0 PID: 2099 Comm: syz-executor936 Tainted: G D 4.4.174+ #17 task: ffff8801d4114740 task.stack: ffff8800b6618000 RIP: 0010:[] [] lookup_object lib/debugobjects.c:120 [inline] RIP: 0010:[] [] debug_object_deactivate+0x16f/0x360 lib/debugobjects.c:468 RSP: 0018:ffff8801db607ce0 EFLAGS: 00010006 RAX: 1ffffffff080f258 RBX: 0000000000000003 RCX: 000000000000c4c2 RDX: 000000000101de03 RSI: ffffffff82eafea0 RDI: 00000000080ef018 RBP: ffff8801db607dd0 R08: 0000000000000001 R09: ffffffff840792c8 R10: 0000000000000096 R11: ffffffff831a5078 R12: 00000000080ef000 R13: dffffc0000000000 R14: 1ffff1003b6c0fa0 R15: ffff8800b6cefd48 FS: 0000000000000000(0000) GS:ffff8801db600000(0063) knlGS:0000000008d4a840 CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 CR2: 00000000000000a6 CR3: 00000000b6d2a000 CR4: 00000000001606b0 Stack: ffff880200000002 ffff880200000000 ffffffff840792c8 ffffffff82eafea0 0000000041b58ab3 ffffffff82c76921 ffffffff81b0c500 ffffffff82c4d560 ffffffff811ff5b0 dffffc0000000001 ffff880100000000 ffffffff00000000 Call Trace: [] debug_hrtimer_deactivate kernel/time/hrtimer.c:415 [inline] [] debug_deactivate kernel/time/hrtimer.c:462 [inline] [] __run_hrtimer kernel/time/hrtimer.c:1230 [inline] [] __hrtimer_run_queues+0x1bd/0xfc0 kernel/time/hrtimer.c:1325 [] hrtimer_interrupt+0x1b6/0x450 kernel/time/hrtimer.c:1359 [] local_apic_timer_interrupt+0x76/0xa0 arch/x86/kernel/apic/apic.c:901 [] smp_apic_timer_interrupt+0x79/0xb0 arch/x86/kernel/apic/apic.c:925 [] apic_timer_interrupt+0x9d/0xb0 arch/x86/entry/entry_64.S:768 [] no_context+0x2b6/0x820 arch/x86/mm/fault.c:733 [] __bad_area_nosemaphore+0x282/0x3f0 arch/x86/mm/fault.c:813 [] bad_area_nosemaphore+0x2b/0x40 arch/x86/mm/fault.c:820 [] __do_page_fault+0x410/0x7f0 arch/x86/mm/fault.c:1185 [] do_page_fault+0x28/0x30 arch/x86/mm/fault.c:1306 [] page_fault+0x25/0x30 arch/x86/entry/entry_64.S:1064 [] anon_vma_chain_alloc mm/rmap.c:124 [inline] [] anon_vma_fork+0x1ce/0x4b0 mm/rmap.c:340 [] dup_mmap kernel/fork.c:471 [inline] [] dup_mm kernel/fork.c:985 [inline] [] copy_mm kernel/fork.c:1039 [inline] [] copy_process+0x412c/0x68a0 kernel/fork.c:1519 [] _do_fork+0x14e/0xdc0 kernel/fork.c:1806 [] SYSC_clone kernel/fork.c:1917 [inline] [] SyS_clone+0x37/0x50 kernel/fork.c:1911 [] do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline] [] do_fast_syscall_32+0x32d/0xa90 arch/x86/entry/common.c:397 [] sysenter_flags_fixed+0xd/0x1a Code: 48 c1 ea 03 42 80 3c 2a 00 0f 85 8e 01 00 00 4d 8b 24 24 4d 85 e4 0f 84 e9 00 00 00 49 8d 7c 24 18 83 c3 01 48 89 fa 48 c1 ea 03 <42> 80 3c 2a 00 0f 85 3f 01 00 00 4d 3b 7c 24 18 75 c0 49 8d 7c RIP [] lookup_object lib/debugobjects.c:120 [inline] RIP [] debug_object_deactivate+0x16f/0x360 lib/debugobjects.c:468 RSP ---[ end trace 0a148c7d09f55266 ]---