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BUG: KASAN: use-after-free in fuse_copy_do fs/fuse/dev.c:753 [inline]
BUG: KASAN: use-after-free in fuse_copy_one+0x1c0/0x3a0 fs/fuse/dev.c:1005
Read of size 256 at addr ffff8881dd2a9010 by task syz-executor.0/462

CPU: 0 PID: 462 Comm: syz-executor.0 Not tainted 5.4.284-syzkaller-04988-g137306201ec6 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1d8/0x241 lib/dump_stack.c:118
 print_address_description+0x8c/0x600 mm/kasan/report.c:384
 __kasan_report+0xf3/0x120 mm/kasan/report.c:516
 kasan_report+0x30/0x60 mm/kasan/common.c:653
 check_memory_region_inline mm/kasan/generic.c:141 [inline]
 check_memory_region+0x272/0x280 mm/kasan/generic.c:191
 memcpy+0x25/0x50 mm/kasan/common.c:123
 fuse_copy_do fs/fuse/dev.c:753 [inline]
 fuse_copy_one+0x1c0/0x3a0 fs/fuse/dev.c:1005
 fuse_copy_args+0x339/0x410 fs/fuse/dev.c:1023
 fuse_dev_do_read+0xc1b/0x1190 fs/fuse/dev.c:1298
 fuse_dev_read+0x179/0x220 fs/fuse/dev.c:1365
 call_read_iter include/linux/fs.h:1983 [inline]
 new_sync_read fs/read_write.c:414 [inline]
 __vfs_read+0x5cd/0x730 fs/read_write.c:427
 vfs_read+0x148/0x360 fs/read_write.c:461
 ksys_read+0x199/0x2c0 fs/read_write.c:587
 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1
RIP: 0033:0x7ff1b1fe9db9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ff1b1b0a0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007ff1b210a1f0 RCX: 00007ff1b1fe9db9
RDX: 0000000000002020 RSI: 0000000020002140 RDI: 0000000000000003
RBP: 00007ff1b2046ad0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000006e R14: 00007ff1b210a1f0 R15: 00007ffe15332df8

Allocated by task 456:
 save_stack mm/kasan/common.c:70 [inline]
 set_track mm/kasan/common.c:78 [inline]
 __kasan_kmalloc+0x171/0x210 mm/kasan/common.c:529
 kmalloc include/linux/slab.h:561 [inline]
 __d_alloc+0xae/0x6a0 fs/dcache.c:1711
 d_alloc fs/dcache.c:1774 [inline]
 d_alloc_parallel+0xec/0x1390 fs/dcache.c:2528
 __lookup_slow+0x156/0x460 fs/namei.c:1731
 lookup_slow+0x53/0x70 fs/namei.c:1765
 walk_component+0x2dc/0x590 fs/namei.c:1885
 lookup_last fs/namei.c:2348 [inline]
 path_lookupat+0x182/0x3f0 fs/namei.c:2393
 filename_lookup+0x253/0x6e0 fs/namei.c:2423
 user_path_at include/linux/namei.h:49 [inline]
 do_mount+0x135/0xe10 fs/namespace.c:3101
 ksys_mount+0xc2/0xf0 fs/namespace.c:3372
 __do_sys_mount fs/namespace.c:3386 [inline]
 __se_sys_mount fs/namespace.c:3383 [inline]
 __x64_sys_mount+0xb1/0xc0 fs/namespace.c:3383
 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1

Freed by task 164:
 save_stack mm/kasan/common.c:70 [inline]
 set_track mm/kasan/common.c:78 [inline]
 kasan_set_free_info mm/kasan/common.c:345 [inline]
 __kasan_slab_free+0x1b5/0x270 mm/kasan/common.c:487
 slab_free_hook mm/slub.c:1455 [inline]
 slab_free_freelist_hook mm/slub.c:1494 [inline]
 slab_free mm/slub.c:3080 [inline]
 kfree+0x123/0x370 mm/slub.c:4071
 __rcu_reclaim kernel/rcu/rcu.h:215 [inline]
 rcu_do_batch+0x451/0xa00 kernel/rcu/tree.c:2167
 rcu_core+0x4c8/0xcb0 kernel/rcu/tree.c:2387
 __do_softirq+0x23b/0x6b7 kernel/softirq.c:292

The buggy address belongs to the object at ffff8881dd2a9000
 which belongs to the cache kmalloc-rcl-512 of size 512
The buggy address is located 16 bytes inside of
 512-byte region [ffff8881dd2a9000, ffff8881dd2a9200)
The buggy address belongs to the page:
page:ffffea000774aa00 refcount:1 mapcount:0 mapping:ffff8881f5c0db80 index:0x0 compound_mapcount: 0
flags: 0x8000000000010200(slab|head)
raw: 8000000000010200 dead000000000100 dead000000000122 ffff8881f5c0db80
raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Reclaimable, gfp_mask 0x1d20d0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL|__GFP_RECLAIMABLE)
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook mm/page_alloc.c:2165 [inline]
 prep_new_page+0x18f/0x370 mm/page_alloc.c:2171
 get_page_from_freelist+0x2d13/0x2d90 mm/page_alloc.c:3794
 __alloc_pages_nodemask+0x393/0x840 mm/page_alloc.c:4893
 alloc_slab_page+0x39/0x3c0 mm/slub.c:343
 allocate_slab mm/slub.c:1683 [inline]
 new_slab+0x97/0x440 mm/slub.c:1749
 new_slab_objects mm/slub.c:2505 [inline]
 ___slab_alloc+0x2fe/0x490 mm/slub.c:2667
 __slab_alloc+0x62/0xa0 mm/slub.c:2707
 slab_alloc_node mm/slub.c:2792 [inline]
 slab_alloc mm/slub.c:2837 [inline]
 __kmalloc+0x19b/0x2e0 mm/slub.c:3909
 kmalloc include/linux/slab.h:561 [inline]
 __d_alloc+0xae/0x6a0 fs/dcache.c:1711
 d_alloc fs/dcache.c:1774 [inline]
 d_alloc_parallel+0xec/0x1390 fs/dcache.c:2528
 __lookup_slow+0x156/0x460 fs/namei.c:1731
 lookup_slow+0x53/0x70 fs/namei.c:1765
 walk_component+0x2dc/0x590 fs/namei.c:1885
 lookup_last fs/namei.c:2348 [inline]
 path_lookupat+0x182/0x3f0 fs/namei.c:2393
 filename_lookup+0x253/0x6e0 fs/namei.c:2423
 user_path_at include/linux/namei.h:49 [inline]
 do_mount+0x135/0xe10 fs/namespace.c:3101
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1176 [inline]
 free_pcp_prepare mm/page_alloc.c:1233 [inline]
 free_unref_page_prepare+0x297/0x380 mm/page_alloc.c:3085
 free_unref_page_list+0x10a/0x590 mm/page_alloc.c:3154
 release_pages+0xad8/0xb20 mm/swap.c:842
 tlb_batch_pages_flush mm/mmu_gather.c:49 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:189 [inline]
 tlb_flush_mmu+0xc8/0x170 mm/mmu_gather.c:196
 zap_pte_range mm/memory.c:1173 [inline]
 zap_pmd_range mm/memory.c:1222 [inline]
 zap_pud_range mm/memory.c:1251 [inline]
 zap_p4d_range mm/memory.c:1272 [inline]
 unmap_page_range+0x1d29/0x2620 mm/memory.c:1293
 unmap_single_vma mm/memory.c:1338 [inline]
 unmap_vmas+0x355/0x4b0 mm/memory.c:1370
 exit_mmap+0x2bc/0x520 mm/mmap.c:3191
 __mmput+0x8e/0x2c0 kernel/fork.c:1101
 exit_mm kernel/exit.c:538 [inline]
 do_exit+0xc08/0x2bc0 kernel/exit.c:848
 do_group_exit+0x138/0x300 kernel/exit.c:984
 get_signal+0xdb1/0x1440 kernel/signal.c:2735
 do_signal+0xb0/0x11f0 arch/x86/kernel/signal.c:809
 exit_to_usermode_loop+0xc0/0x1a0 arch/x86/entry/common.c:159
 prepare_exit_to_usermode+0x199/0x200 arch/x86/entry/common.c:194
 swapgs_restore_regs_and_return_to_usermode+0x0/0x54

Memory state around the buggy address:
 ffff8881dd2a8f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8881dd2a8f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8881dd2a9000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                         ^
 ffff8881dd2a9080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881dd2a9100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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