================================================================== BUG: KASAN: use-after-free in dev_expire_timer+0x2e2/0x3b0 drivers/isdn/mISDN/timerdev.c:174 Read of size 8 at addr ffff8880a9b1f850 by task syz-executor0/22914 CPU: 0 PID: 22914 Comm: syz-executor0 Not tainted 5.0.0-rc5-next-20190205 #28 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+0x172/0x1f0 lib/dump_stack.c:113 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187 kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:132 dev_expire_timer+0x2e2/0x3b0 drivers/isdn/mISDN/timerdev.c:174 call_timer_fn+0x190/0x720 kernel/time/timer.c:1325 expire_timers kernel/time/timer.c:1362 [inline] __run_timers kernel/time/timer.c:1681 [inline] __run_timers kernel/time/timer.c:1649 [inline] run_timer_softirq+0x652/0x1700 kernel/time/timer.c:1694 __do_softirq+0x266/0x95a kernel/softirq.c:292 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x180/0x1d0 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:536 [inline] smp_apic_timer_interrupt+0x14a/0x570 arch/x86/kernel/apic/apic.c:1062 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807 RIP: 0010:rcu_lockdep_current_cpu_online kernel/rcu/tree.c:1004 [inline] RIP: 0010:rcu_lockdep_current_cpu_online+0x86/0x130 kernel/rcu/tree.c:994 Code: 3c 11 00 0f 85 9d 00 00 00 48 03 1c c5 60 70 6f 88 48 b8 00 00 00 00 00 fc ff df 48 8d 7b 18 48 89 fa 48 c1 ea 03 80 3c 02 00 <0f> 85 88 00 00 00 48 8d 7b 20 4c 8b 63 18 48 b8 00 00 00 00 00 fc RSP: 0018:ffff88804e3079d8 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: dffffc0000000000 RBX: ffff8880ae82dd40 RCX: 1ffffffff10dee0c RDX: 1ffff11015d05bab RSI: ffffffff832d5ef8 RDI: ffff8880ae82dd58 RBP: ffff88804e3079f0 R08: ffff88804e4c6100 R09: ffffed1015d05bc0 R10: ffffed1015d05bbf R11: ffff8880ae82ddfb R12: ffff888041bff5c0 R13: ffff88808fdbd680 R14: 0000000000000000 R15: dffffc0000000000 rcu_read_lock_held+0x8a/0xd0 kernel/rcu/update.c:279 __in6_dev_get include/net/addrconf.h:355 [inline] igmp6_mcf_get_first net/ipv6/mcast.c:2802 [inline] igmp6_mcf_seq_next+0x320/0x4a0 net/ipv6/mcast.c:2874 seq_read+0x9ef/0x1130 fs/seq_file.c:258 proc_reg_read+0x1fe/0x2c0 fs/proc/inode.c:227 do_loop_readv_writev fs/read_write.c:700 [inline] do_loop_readv_writev fs/read_write.c:687 [inline] do_iter_read+0x4a9/0x660 fs/read_write.c:921 vfs_readv+0xf0/0x160 fs/read_write.c:983 do_preadv+0x1c4/0x280 fs/read_write.c:1067 __do_sys_preadv fs/read_write.c:1117 [inline] __se_sys_preadv fs/read_write.c:1112 [inline] __x64_sys_preadv+0x9a/0xf0 fs/read_write.c:1112 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457e39 Code: ad b8 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 b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f89671ccc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000127 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000457e39 RDX: 0000000000000324 RSI: 00000000200017c0 RDI: 0000000000000004 RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f89671cd6d4 R13: 00000000004c48e1 R14: 00000000004d8060 R15: 00000000ffffffff Allocated by task 23198: save_stack+0x45/0xd0 mm/kasan/common.c:75 set_track mm/kasan/common.c:87 [inline] __kasan_kmalloc mm/kasan/common.c:498 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:471 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:506 kmem_cache_alloc_trace+0x151/0x760 mm/slab.c:3609 kmalloc include/linux/slab.h:548 [inline] kzalloc include/linux/slab.h:743 [inline] misdn_add_timer drivers/isdn/mISDN/timerdev.c:188 [inline] mISDN_ioctl+0x40c/0x9c0 drivers/isdn/mISDN/timerdev.c:242 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0xd6e/0x1390 fs/ioctl.c:696 ksys_ioctl+0xab/0xd0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 23195: save_stack+0x45/0xd0 mm/kasan/common.c:75 set_track mm/kasan/common.c:87 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:460 kasan_slab_free+0xe/0x10 mm/kasan/common.c:468 __cache_free mm/slab.c:3487 [inline] kfree+0xcf/0x230 mm/slab.c:3806 mISDN_close+0x27b/0x390 drivers/isdn/mISDN/timerdev.c:95 __fput+0x2df/0x8d0 fs/file_table.c:278 ____fput+0x16/0x20 fs/file_table.c:309 task_work_run+0x14a/0x1c0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x273/0x2c0 arch/x86/entry/common.c:166 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline] syscall_return_slowpath arch/x86/entry/common.c:268 [inline] do_syscall_64+0x52d/0x610 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff8880a9b1f840 which belongs to the cache kmalloc-128 of size 128 The buggy address is located 16 bytes inside of 128-byte region [ffff8880a9b1f840, ffff8880a9b1f8c0) The buggy address belongs to the page: page:ffffea0002a6c7c0 count:1 mapcount:0 mapping:ffff88812c3f0640 index:0xffff8880a9b1fe40 flags: 0x1fffc0000000200(slab) raw: 01fffc0000000200 ffffea000243ec48 ffffea00025d8508 ffff88812c3f0640 raw: ffff8880a9b1fe40 ffff8880a9b1f000 0000000100000008 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880a9b1f700: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff8880a9b1f780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880a9b1f800: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ^ ffff8880a9b1f880: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff8880a9b1f900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================