audit: type=1400 audit(1575066382.902:41): avc: denied { read } for pid=6989 comm="syz-executor.0" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=1 ===================================== WARNING: bad unlock balance detected! 4.14.156-syzkaller #0 Not tainted ------------------------------------- syz-executor.0/7127 is trying to release lock (&file->mut) at: [] ucma_destroy_id+0x20d/0x420 drivers/infiniband/core/ucma.c:606 but there are no more locks to release! other info that might help us debug this: 1 lock held by syz-executor.0/7127: #0: (&file->mut){+.+.}, at: [] ucma_destroy_id+0x1aa/0x420 drivers/infiniband/core/ucma.c:604 stack backtrace: CPU: 0 PID: 7127 Comm: syz-executor.0 Not tainted 4.14.156-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x142/0x197 lib/dump_stack.c:58 print_unlock_imbalance_bug kernel/locking/lockdep.c:3548 [inline] print_unlock_imbalance_bug.cold+0x114/0x123 kernel/locking/lockdep.c:3525 __lock_release kernel/locking/lockdep.c:3765 [inline] lock_release+0x616/0x940 kernel/locking/lockdep.c:4013 __mutex_unlock_slowpath+0x71/0x800 kernel/locking/mutex.c:1018 mutex_unlock+0xd/0x10 kernel/locking/mutex.c:614 ucma_destroy_id+0x20d/0x420 drivers/infiniband/core/ucma.c:606 ucma_write+0x231/0x310 drivers/infiniband/core/ucma.c:1672 __vfs_write+0x105/0x6b0 fs/read_write.c:480 vfs_write+0x198/0x500 fs/read_write.c:544 SYSC_write fs/read_write.c:590 [inline] SyS_write+0xfd/0x230 fs/read_write.c:582 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x45a679 RSP: 002b:00007f672fc38c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045a679 RDX: 0000000000000018 RSI: 0000000020000140 RDI: 0000000000000003 RBP: 000000000075bfc8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f672fc396d4 R13: 00000000004d2b20 R14: 00000000004e3ba8 R15: 00000000ffffffff ================================================================== BUG: KASAN: use-after-free in __read_once_size include/linux/compiler.h:183 [inline] BUG: KASAN: use-after-free in atomic64_read arch/x86/include/asm/atomic64_64.h:22 [inline] BUG: KASAN: use-after-free in atomic_long_read include/asm-generic/atomic-long.h:45 [inline] BUG: KASAN: use-after-free in __mutex_unlock_slowpath+0x656/0x800 kernel/locking/mutex.c:1027 Read of size 8 at addr ffff88808835f040 by task syz-executor.0/7127 CPU: 0 PID: 7127 Comm: syz-executor.0 Not tainted 4.14.156-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x142/0x197 lib/dump_stack.c:58 print_address_description.cold+0x7c/0x1dc mm/kasan/report.c:252 kasan_report_error mm/kasan/report.c:351 [inline] kasan_report mm/kasan/report.c:409 [inline] kasan_report.cold+0xa9/0x2af mm/kasan/report.c:393 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:430 __read_once_size include/linux/compiler.h:183 [inline] atomic64_read arch/x86/include/asm/atomic64_64.h:22 [inline] atomic_long_read include/asm-generic/atomic-long.h:45 [inline] __mutex_unlock_slowpath+0x656/0x800 kernel/locking/mutex.c:1027 mutex_unlock+0xd/0x10 kernel/locking/mutex.c:614 ucma_destroy_id+0x20d/0x420 drivers/infiniband/core/ucma.c:606 ucma_write+0x231/0x310 drivers/infiniband/core/ucma.c:1672 __vfs_write+0x105/0x6b0 fs/read_write.c:480 vfs_write+0x198/0x500 fs/read_write.c:544 SYSC_write fs/read_write.c:590 [inline] SyS_write+0xfd/0x230 fs/read_write.c:582 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x45a679 RSP: 002b:00007f672fc38c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045a679 RDX: 0000000000000018 RSI: 0000000020000140 RDI: 0000000000000003 RBP: 000000000075bfc8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f672fc396d4 R13: 00000000004d2b20 R14: 00000000004e3ba8 R15: 00000000ffffffff Allocated by task 7130: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 save_stack+0x45/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc mm/kasan/kasan.c:551 [inline] kasan_kmalloc+0xce/0xf0 mm/kasan/kasan.c:529 kmem_cache_alloc_trace+0x152/0x790 mm/slab.c:3618 kmalloc include/linux/slab.h:488 [inline] ucma_open+0x4f/0x290 drivers/infiniband/core/ucma.c:1704 misc_open+0x34f/0x480 drivers/char/misc.c:154 chrdev_open+0x207/0x590 fs/char_dev.c:423 do_dentry_open+0x73b/0xeb0 fs/open.c:777 vfs_open+0x105/0x220 fs/open.c:891 do_last fs/namei.c:3425 [inline] path_openat+0x8bd/0x3f70 fs/namei.c:3566 do_filp_open+0x18e/0x250 fs/namei.c:3600 do_sys_open+0x2c5/0x430 fs/open.c:1084 SYSC_openat fs/open.c:1111 [inline] SyS_openat+0x30/0x40 fs/open.c:1105 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 Freed by task 7122: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 save_stack+0x45/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_slab_free+0x75/0xc0 mm/kasan/kasan.c:524 __cache_free mm/slab.c:3496 [inline] kfree+0xcc/0x270 mm/slab.c:3815 ucma_close+0x280/0x310 drivers/infiniband/core/ucma.c:1763 __fput+0x275/0x7a0 fs/file_table.c:210 ____fput+0x16/0x20 fs/file_table.c:244 task_work_run+0x114/0x190 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:191 [inline] exit_to_usermode_loop+0x1da/0x220 arch/x86/entry/common.c:164 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline] syscall_return_slowpath arch/x86/entry/common.c:270 [inline] do_syscall_64+0x4bc/0x640 arch/x86/entry/common.c:297 entry_SYSCALL_64_after_hwframe+0x42/0xb7 The buggy address belongs to the object at ffff88808835f040 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 0 bytes inside of 256-byte region [ffff88808835f040, ffff88808835f140) The buggy address belongs to the page: page:ffffea000220d7c0 count:1 mapcount:0 mapping:ffff88808835f040 index:0xffff88808835fe00 flags: 0xfffe0000000100(slab) raw: 00fffe0000000100 ffff88808835f040 ffff88808835fe00 0000000100000008 raw: ffffea00028fbfe0 ffffea000293db20 ffff8880aa8007c0 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88808835ef00: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ffff88808835ef80: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc >ffff88808835f000: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ^ ffff88808835f080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88808835f100: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc 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