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BUG: KASAN: use-after-free in constant_test_bit arch/x86/include/asm/bitops.h:328 [inline]
BUG: KASAN: use-after-free in fuse_dev_do_read.isra.27+0x1659/0x1920 fs/fuse/dev.c:1318
Read of size 8 at addr ffff880157eb8e30 by task syz-executor4/1156

CPU: 0 PID: 1156 Comm: syz-executor4 Not tainted 4.19.0-rc3+ #13
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+0x1c4/0x2b4 lib/dump_stack.c:113
 print_address_description.cold.8+0x9/0x1ff mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.9+0x242/0x309 mm/kasan/report.c:412
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
 constant_test_bit arch/x86/include/asm/bitops.h:328 [inline]
 fuse_dev_do_read.isra.27+0x1659/0x1920 fs/fuse/dev.c:1318
 fuse_dev_read+0x1a9/0x250 fs/fuse/dev.c:1360
 call_read_iter include/linux/fs.h:1801 [inline]
 new_sync_read fs/read_write.c:406 [inline]
 __vfs_read+0x6ac/0x9b0 fs/read_write.c:418
 vfs_read+0x17f/0x3c0 fs/read_write.c:452
 ksys_read+0x101/0x260 fs/read_write.c:578
 __do_sys_read fs/read_write.c:588 [inline]
 __se_sys_read fs/read_write.c:586 [inline]
 __x64_sys_read+0x73/0xb0 fs/read_write.c:586
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4572d9
Code: fd 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 cb b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f5157429c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f515742a6d4 RCX: 00000000004572d9
RDX: 0000000000001000 RSI: 0000000020001000 RDI: 0000000000000005
RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004d4508 R14: 00000000004c8d44 R15: 0000000000000000

Allocated by task 1175:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553
 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:490
 kmem_cache_alloc+0x12e/0x730 mm/slab.c:3554
 __fuse_request_alloc+0x27/0xf0 fs/fuse/dev.c:58
 fuse_request_alloc fs/fuse/dev.c:89 [inline]
 __fuse_get_req+0x1f7/0x9e0 fs/fuse/dev.c:164
 fuse_get_req fs/fuse/dev.c:194 [inline]
 fuse_simple_request+0x28/0x730 fs/fuse/dev.c:549
 fuse_lookup_name+0x3ee/0x830 fs/fuse/dir.c:323
 fuse_lookup+0xff/0x4c0 fs/fuse/dir.c:361
 __lookup_slow+0x2b5/0x540 fs/namei.c:1671
 lookup_slow+0x57/0x80 fs/namei.c:1688
 walk_component+0x92b/0x25c0 fs/namei.c:1810
 lookup_last fs/namei.c:2273 [inline]
 path_lookupat.isra.43+0x212/0xc00 fs/namei.c:2318
 filename_lookup+0x26a/0x520 fs/namei.c:2348
 user_path_at_empty+0x40/0x50 fs/namei.c:2608
 user_path_at include/linux/namei.h:57 [inline]
 vfs_statx+0x129/0x210 fs/stat.c:185
 vfs_stat include/linux/fs.h:3123 [inline]
 __do_sys_newstat+0x8f/0x110 fs/stat.c:337
 __se_sys_newstat fs/stat.c:333 [inline]
 __x64_sys_newstat+0x54/0x80 fs/stat.c:333
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 1175:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521
 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
 __cache_free mm/slab.c:3498 [inline]
 kmem_cache_free+0x83/0x290 mm/slab.c:3756
 fuse_request_free+0x8b/0xa0 fs/fuse/dev.c:104
 fuse_put_request+0x2a6/0x350 fs/fuse/dev.c:304
 fuse_simple_request+0x453/0x730 fs/fuse/dev.c:571
 fuse_lookup_name+0x3ee/0x830 fs/fuse/dir.c:323
 fuse_lookup+0xff/0x4c0 fs/fuse/dir.c:361
 __lookup_slow+0x2b5/0x540 fs/namei.c:1671
 lookup_slow+0x57/0x80 fs/namei.c:1688
 walk_component+0x92b/0x25c0 fs/namei.c:1810
 lookup_last fs/namei.c:2273 [inline]
 path_lookupat.isra.43+0x212/0xc00 fs/namei.c:2318
 filename_lookup+0x26a/0x520 fs/namei.c:2348
 user_path_at_empty+0x40/0x50 fs/namei.c:2608
 user_path_at include/linux/namei.h:57 [inline]
 vfs_statx+0x129/0x210 fs/stat.c:185
 vfs_stat include/linux/fs.h:3123 [inline]
 __do_sys_newstat+0x8f/0x110 fs/stat.c:337
 __se_sys_newstat fs/stat.c:333 [inline]
 __x64_sys_newstat+0x54/0x80 fs/stat.c:333
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff880157eb8e00
 which belongs to the cache fuse_request of size 448
The buggy address is located 48 bytes inside of
 448-byte region [ffff880157eb8e00, ffff880157eb8fc0)
The buggy address belongs to the page:
page:ffffea00055fae00 count:1 mapcount:0 mapping:ffff8801d4f3e900 index:0x0
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffffea0006e32f48 ffff8801d4f3c548 ffff8801d4f3e900
raw: 0000000000000000 ffff880157eb8000 0000000100000008 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff880157eb8d00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff880157eb8d80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff880157eb8e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                     ^
 ffff880157eb8e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff880157eb8f00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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