BUG: KASAN: use-after-free in ex_handler_refcount+0x14b/0x170 arch/x86/mm/extable.c:57
Write of size 4 at addr ffff8881cb655f80 by task syz-executor.0/824

CPU: 1 PID: 824 Comm: syz-executor.0 Not tainted 5.4.61-syzkaller-00823-g34364883b1f7 #0
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+0x14a/0x1ce lib/dump_stack.c:118
 print_address_description+0x93/0x620 mm/kasan/report.c:374
 __kasan_report+0x16d/0x1e0 mm/kasan/report.c:506
 kasan_report+0x36/0x60 mm/kasan/common.c:634
 ex_handler_refcount+0x14b/0x170 arch/x86/mm/extable.c:57
 fixup_exception+0x92/0xd0 arch/x86/mm/extable.c:228
 do_trap_no_signal arch/x86/kernel/traps.c:207 [inline]
 do_trap+0x148/0x340 arch/x86/kernel/traps.c:251
 do_error_trap arch/x86/kernel/traps.c:278 [inline]
 do_invalid_op+0xfb/0x110 arch/x86/kernel/traps.c:291
 invalid_op+0x1e/0x30 arch/x86/entry/entry_64.S:1029
RIP: 0010:csum_partial_copy_generic+0xa2e/0x3ed0
Code: 0f 0b 49 8d 0f 0f 0b 49 8d 4d f4 0f 0b 48 8d 4d 00 0f 0b 49 8d 0e 0f 0b 49 8d 0e 0f 0b 49 8d 0f 0f 0b 48 8d 08 0f 0b 49 8d 0f <0f> 0b 49 8d 8c 24 b0 00 00 00 0f 0b 48 8d 8b 94 00 00 00 0f 0b 48
RSP: 0018:ffff8881c95b7e38 EFLAGS: 00010296
RAX: d671d67de4fcf700 RBX: ffff8881c9a56988 RCX: ffff8881cb655f80
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: ffff8881cb655f88
RBP: dffffc0000000000 R08: 0000000000000010 R09: ffff8881c95b7d80
R10: ffffed10396cabf2 R11: 0000000000000000 R12: ffff8881c9a568c0
R13: 1ffff1103b2fdbca R14: 00000000000e0003 R15: ffff8881cb655f80
 __fput+0x27d/0x6c0 fs/file_table.c:280
 task_work_run+0x176/0x1a0 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop arch/x86/entry/common.c:163 [inline]
 prepare_exit_to_usermode+0x286/0x2e0 arch/x86/entry/common.c:194
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45d5b9
Code: 5d b4 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 2b b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f459f6f8c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000e9
RAX: 0000000000000000 RBX: 0000000000002ac0 RCX: 000000000045d5b9
RDX: 0000000000000005 RSI: 0000000000000001 RDI: 0000000000000006
RBP: 000000000118cf88 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000020000040 R11: 0000000000000246 R12: 000000000118cf4c
R13: 00007ffc1374f10f R14: 00007f459f6f99c0 R15: 000000000118cf4c

Allocated by task 824:
 save_stack mm/kasan/common.c:69 [inline]
 set_track mm/kasan/common.c:77 [inline]
 __kasan_kmalloc+0x12c/0x1c0 mm/kasan/common.c:510
 kmem_cache_alloc_trace+0xc3/0x280 mm/slub.c:2820
 kmalloc include/linux/slab.h:556 [inline]
 do_eventfd+0x81/0x250 fs/eventfd.c:418
 __do_sys_eventfd2 fs/eventfd.c:438 [inline]
 __se_sys_eventfd2 fs/eventfd.c:436 [inline]
 __x64_sys_eventfd2+0x56/0x60 fs/eventfd.c:436
 do_syscall_64+0xcb/0x150 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 823:
 save_stack mm/kasan/common.c:69 [inline]
 set_track mm/kasan/common.c:77 [inline]
 kasan_set_free_info mm/kasan/common.c:332 [inline]
 __kasan_slab_free+0x181/0x230 mm/kasan/common.c:471
 slab_free_hook mm/slub.c:1443 [inline]
 slab_free_freelist_hook+0xd0/0x150 mm/slub.c:1476
 slab_free mm/slub.c:3041 [inline]
 kfree+0x12b/0x600 mm/slub.c:4002
 eventfd_free_ctx fs/eventfd.c:94 [inline]
 eventfd_free fs/eventfd.c:101 [inline]
 kref_put include/linux/kref.h:65 [inline]
 eventfd_ctx_put fs/eventfd.c:113 [inline]
 eventfd_release+0xbb/0xe0 fs/eventfd.c:122
 __fput+0x27d/0x6c0 fs/file_table.c:280
 task_work_run+0x176/0x1a0 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop arch/x86/entry/common.c:163 [inline]
 prepare_exit_to_usermode+0x286/0x2e0 arch/x86/entry/common.c:194
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff8881cb655f80
 which belongs to the cache kmalloc-64 of size 64
The buggy address is located 0 bytes inside of
 64-byte region [ffff8881cb655f80, ffff8881cb655fc0)
The buggy address belongs to the page:
page:ffffea00072d9540 refcount:1 mapcount:0 mapping:ffff8881da803180 index:0x0
flags: 0x8000000000000200(slab)
raw: 8000000000000200 dead000000000100 dead000000000122 ffff8881da803180
raw: 0000000000000000 0000000080200020 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8881cb655e80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff8881cb655f00: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>ffff8881cb655f80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
                   ^
 ffff8881cb656000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881cb656080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

CPU: 1 PID: 824 Comm: syz-executor.0 Tainted: G    B             5.4.61-syzkaller-00823-g34364883b1f7 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x14a/0x1ce lib/dump_stack.c:118
 print_address_description+0x93/0x620 mm/kasan/report.c:374
 kasan_report_invalid_free+0x54/0xc0 mm/kasan/report.c:468
 __kasan_slab_free+0x102/0x230 mm/kasan/common.c:459
 slab_free_hook mm/slub.c:1443 [inline]
 slab_free_freelist_hook+0xd0/0x150 mm/slub.c:1476
 slab_free mm/slub.c:3041 [inline]
 kmem_cache_free+0xac/0x600 mm/slub.c:3057
 dentry_kill fs/dcache.c:673 [inline]
 dput+0x2e1/0x5e0 fs/dcache.c:859
 __fput+0x46b/0x6c0 fs/file_table.c:293
 task_work_run+0x176/0x1a0 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop arch/x86/entry/common.c:163 [inline]
 prepare_exit_to_usermode+0x286/0x2e0 arch/x86/entry/common.c:194
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45d5b9
Code: 5d b4 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 2b b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f459f6f8c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000e9
RAX: 0000000000000000 RBX: 0000000000002ac0 RCX: 000000000045d5b9
RDX: 0000000000000005 RSI: 0000000000000001 RDI: 0000000000000006
RBP: 000000000118cf88 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000020000040 R11: 0000000000000246 R12: 000000000118cf4c
R13: 00007ffc1374f10f R14: 00007f459f6f99c0 R15: 000000000118cf4c

Allocated by task 824:
 save_stack mm/kasan/common.c:69 [inline]
 set_track mm/kasan/common.c:77 [inline]
 __kasan_kmalloc+0x12c/0x1c0 mm/kasan/common.c:510
 slab_post_alloc_hook mm/slab.h:584 [inline]
 slab_alloc_node mm/slub.c:2793 [inline]
 slab_alloc mm/slub.c:2801 [inline]
 kmem_cache_alloc+0x1d5/0x260 mm/slub.c:2806
 __d_alloc+0x2a/0x6b0 fs/dcache.c:1688
 d_alloc_pseudo+0x19/0x70 fs/dcache.c:1817
 alloc_file_pseudo+0x15b/0x340 fs/file_table.c:225
 anon_inode_getfile+0xa7/0x170 fs/anon_inodes.c:91
 anon_inode_getfd+0x3e/0x80 fs/anon_inodes.c:136
 do_eventfd+0x16b/0x250 fs/eventfd.c:428
 __do_sys_eventfd2 fs/eventfd.c:438 [inline]
 __se_sys_eventfd2 fs/eventfd.c:436 [inline]
 __x64_sys_eventfd2+0x56/0x60 fs/eventfd.c:436
 do_syscall_64+0xcb/0x150 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 823:
 save_stack mm/kasan/common.c:69 [inline]
 set_track mm/kasan/common.c:77 [inline]
 kasan_set_free_info mm/kasan/common.c:332 [inline]
 __kasan_slab_free+0x181/0x230 mm/kasan/common.c:471
 slab_free_hook mm/slub.c:1443 [inline]
 slab_free_freelist_hook+0xd0/0x150 mm/slub.c:1476
 slab_free mm/slub.c:3041 [inline]
 kmem_cache_free+0xac/0x600 mm/slub.c:3057
 dentry_kill fs/dcache.c:673 [inline]
 dput+0x2e1/0x5e0 fs/dcache.c:859
 __fput+0x46b/0x6c0 fs/file_table.c:293
 task_work_run+0x176/0x1a0 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop arch/x86/entry/common.c:163 [inline]
 prepare_exit_to_usermode+0x286/0x2e0 arch/x86/entry/common.c:194
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff8881d3a52770
 which belongs to the cache dentry of size 208
The buggy address is located 0 bytes inside of
 208-byte region [ffff8881d3a52770, ffff8881d3a52840)
The buggy address belongs to the page:
page:ffffea00074e9480 refcount:1 mapcount:0 mapping:ffff8881da8ef900 index:0x0
flags: 0x8000000000000200(slab)
raw: 8000000000000200 dead000000000100 dead000000000122 ffff8881da8ef900
raw: 0000000000000000 00000000800f000f 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8881d3a52600: 00 00 00 00 fc fc fc fc fc fc fc fc 00 00 00 00
 ffff8881d3a52680: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8881d3a52700: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fb fb
                                                             ^
 ffff8881d3a52780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881d3a52800: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
==================================================================