RSP = 0x0000000000000000 RIP = 0x0000000000000000 RFLAGS=0x0001a202 DR7 = 0x0000000000000400 Sysenter RSP=0000000000000000 CS:RIP=0000:0000000000000000 ================================================================== CS: sel=0xf000, attr=0x0009b, limit=0x0000ffff, base=0x00000000ffff0000 BUG: KASAN: use-after-free in atomic64_read include/asm-generic/atomic-instrumented.h:27 [inline] BUG: KASAN: use-after-free in atomic_long_read include/asm-generic/atomic-long.h:47 [inline] BUG: KASAN: use-after-free in __mutex_trylock_or_owner kernel/locking/mutex.c:84 [inline] BUG: KASAN: use-after-free in __mutex_trylock kernel/locking/mutex.c:125 [inline] BUG: KASAN: use-after-free in __mutex_lock_common kernel/locking/mutex.c:927 [inline] BUG: KASAN: use-after-free in __mutex_lock+0x185/0x1680 kernel/locking/mutex.c:1073 Read of size 8 at addr ffff8801c6bc40b8 by task kworker/1:2/4739 CPU: 1 PID: 4739 Comm: kworker/1:2 Not tainted 4.18.0-rc4-next-20180711+ #4 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events p9_poll_workfn Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1c9/0x2b4 lib/dump_stack.c:113 DS: sel=0x0000, attr=0x00093, limit=0x0000ffff, base=0x0000000000000000 SS: sel=0x0000, attr=0x00093, limit=0x0000ffff, base=0x0000000000000000 print_address_description+0x6c/0x20b mm/kasan/report.c:256 ES: sel=0x0000, attr=0x00093, limit=0x0000ffff, base=0x0000000000000000 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report.cold.7+0x242/0x30d mm/kasan/report.c:412 check_memory_region_inline mm/kasan/kasan.c:260 [inline] check_memory_region+0x13e/0x1b0 mm/kasan/kasan.c:267 FS: sel=0x0000, attr=0x00093, limit=0x0000ffff, base=0x0000000000000000 kasan_check_read+0x11/0x20 mm/kasan/kasan.c:272 atomic64_read include/asm-generic/atomic-instrumented.h:27 [inline] atomic_long_read include/asm-generic/atomic-long.h:47 [inline] __mutex_trylock_or_owner kernel/locking/mutex.c:84 [inline] __mutex_trylock kernel/locking/mutex.c:125 [inline] __mutex_lock_common kernel/locking/mutex.c:927 [inline] __mutex_lock+0x185/0x1680 kernel/locking/mutex.c:1073 GS: sel=0x0000, attr=0x00093, limit=0x0000ffff, base=0x0000000000000000 GDTR: limit=0x0000ffff, base=0x0000000000000000 LDTR: sel=0x0000, attr=0x00082, limit=0x0000ffff, base=0x0000000000000000 IDTR: limit=0x0000ffff, base=0x0000000000000000 TR: sel=0x0000, attr=0x0008b, limit=0x0000ffff, base=0x0000000000000000 EFER = 0x0000000000000000 PAT = 0x0007040600070406 DebugCtl = 0x0000000000000000 DebugExceptions = 0x0000000000000000 Interruptibility = 00000000 ActivityState = 00000000 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1088 *** Host State *** ep_scan_ready_list+0xb77/0xf50 fs/eventpoll.c:681 RIP = 0xffffffff811f4fc4 RSP = 0xffff8801b573f350 CS=0010 SS=0018 DS=0000 ES=0000 FS=0000 GS=0000 TR=0040 FSBase=00007fdd478df700 GSBase=ffff8801dae00000 TRBase=fffffe0000003000 GDTBase=fffffe0000001000 IDTBase=fffffe0000000000 ep_eventpoll_poll+0x192/0x200 fs/eventpoll.c:937 CR0=0000000080050033 CR3=00000001d8adf000 CR4=00000000001426f0 Sysenter RSP=fffffe0000002200 CS:RIP=0010:ffffffff87a01380 vfs_poll include/linux/poll.h:86 [inline] p9_fd_poll+0x1ce/0x2b0 net/9p/trans_fd.c:248 p9_poll_mux net/9p/trans_fd.c:617 [inline] p9_poll_workfn+0x463/0x6d0 net/9p/trans_fd.c:1107 EFER = 0x0000000000000d01 PAT = 0x0000000000000000 *** Control State *** PinBased=0000003f CPUBased=b5a06dfa SecondaryExec=000000c3 EntryControls=0000d1ff ExitControls=0023efff process_one_work+0xc73/0x1ba0 kernel/workqueue.c:2153 ExceptionBitmap=00060042 PFECmask=00000000 PFECmatch=00000000 VMEntry: intr_info=80000081 errcode=00000000 ilen=00000000 VMExit: intr_info=00000000 errcode=00000000 ilen=00000000 reason=80000021 qualification=0000000000000000 IDTVectoring: info=00000000 errcode=00000000 TSC Offset = 0xfffffc7e0e51260d TPR Threshold = 0x00 worker_thread+0x189/0x13c0 kernel/workqueue.c:2296 EPT pointer = 0x00000001d84b201e kthread+0x345/0x410 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:415 Allocated by task 25055: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:553 kmem_cache_alloc_trace+0x152/0x780 mm/slab.c:3620 kmalloc include/linux/slab.h:513 [inline] kzalloc include/linux/slab.h:707 [inline] ep_alloc fs/eventpoll.c:1016 [inline] do_epoll_create+0x170/0x5c0 fs/eventpoll.c:1952 __do_sys_epoll_create1 fs/eventpoll.c:1983 [inline] __se_sys_epoll_create1 fs/eventpoll.c:1981 [inline] __x64_sys_epoll_create1+0x31/0x40 fs/eventpoll.c:1981 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 25055: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:521 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 __cache_free mm/slab.c:3498 [inline] kfree+0xd9/0x260 mm/slab.c:3813 ep_free+0x273/0x310 fs/eventpoll.c:856 ep_eventpoll_release+0x44/0x60 fs/eventpoll.c:864 __fput+0x35d/0x930 fs/file_table.c:252 ____fput+0x15/0x20 fs/file_table.c:288 task_work_run+0x1ec/0x2a0 kernel/task_work.c:113 get_signal+0x1557/0x1970 kernel/signal.c:2297 do_signal+0x9c/0x21c0 arch/x86/kernel/signal.c:816 exit_to_usermode_loop+0x2e5/0x380 arch/x86/entry/common.c:162 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline] syscall_return_slowpath arch/x86/entry/common.c:268 [inline] do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff8801c6bc4080 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 56 bytes inside of 512-byte region [ffff8801c6bc4080, ffff8801c6bc4280) The buggy address belongs to the page: page:ffffea00071af100 count:1 mapcount:0 mapping:ffff8801da800940 index:0xffff8801c6bc4300 flags: 0x2fffc0000000100(slab) raw: 02fffc0000000100 ffffea0006c0cc88 ffffea00072895c8 ffff8801da800940 raw: ffff8801c6bc4300 ffff8801c6bc4080 0000000100000005 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801c6bc3f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8801c6bc4000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8801c6bc4080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8801c6bc4100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801c6bc4180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================