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BUG: KASAN: slab-out-of-bounds in iov_iter_revert+0x1c1/0x5a0 lib/iov_iter.c:633
Read of size 4 at addr ffff888031b9d718 by task kworker/u8:8/3001

CPU: 1 UID: 0 PID: 3001 Comm: kworker/u8:8 Not tainted 6.14.0-syzkaller-13423-ga8662bcd2ff1 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Workqueue: events_unbound netfs_write_collection_worker
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0x16e/0x5b0 mm/kasan/report.c:521
 kasan_report+0x143/0x180 mm/kasan/report.c:634
 iov_iter_revert+0x1c1/0x5a0 lib/iov_iter.c:633
 netfs_retry_write_stream fs/netfs/write_retry.c:44 [inline]
 netfs_retry_writes+0x17f2/0x19d0 fs/netfs/write_retry.c:231
 netfs_collect_write_results fs/netfs/write_collect.c:352 [inline]
 netfs_write_collection_worker+0x2fc0/0x3bf0 fs/netfs/write_collect.c:374
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xac3/0x18e0 kernel/workqueue.c:3319
 worker_thread+0x870/0xd50 kernel/workqueue.c:3400
 kthread+0x7b7/0x940 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 7833:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0x9d/0xb0 mm/kasan/common.c:394
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __do_kmalloc_node mm/slub.c:4331 [inline]
 __kmalloc_noprof+0x28e/0x4d0 mm/slub.c:4343
 kmalloc_noprof include/linux/slab.h:909 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 lsm_blob_alloc security/security.c:684 [inline]
 lsm_task_alloc security/security.c:771 [inline]
 security_task_alloc+0x4a/0x340 security/security.c:3160
 copy_process+0x1605/0x3d10 kernel/fork.c:2411
 kernel_clone+0x227/0x880 kernel/fork.c:2844
 __do_sys_clone3 kernel/fork.c:3148 [inline]
 __se_sys_clone3+0x348/0x380 kernel/fork.c:3127
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888031b9d700
 which belongs to the cache kmalloc-16 of size 16
The buggy address is located 8 bytes to the right of
 allocated 16-byte region [ffff888031b9d700, ffff888031b9d710)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x31b9d
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000000 ffff88801b041640 dead000000000100 dead000000000122
raw: 0000000000000000 0000000080800080 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x52c40(GFP_NOFS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 54, tgid 54 (kworker/u8:3), ts 172384026325, free_ts 172224542265
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f4/0x240 mm/page_alloc.c:1717
 prep_new_page mm/page_alloc.c:1725 [inline]
 get_page_from_freelist+0x351d/0x36b0 mm/page_alloc.c:3652
 __alloc_frozen_pages_noprof+0x211/0x5b0 mm/page_alloc.c:4934
 alloc_pages_mpol+0x339/0x690 mm/mempolicy.c:2301
 alloc_slab_page mm/slub.c:2459 [inline]
 allocate_slab+0x8f/0x3a0 mm/slub.c:2623
 new_slab mm/slub.c:2676 [inline]
 ___slab_alloc+0xc3b/0x1500 mm/slub.c:3862
 __slab_alloc+0x58/0xa0 mm/slub.c:3952
 __slab_alloc_node mm/slub.c:4027 [inline]
 slab_alloc_node mm/slub.c:4188 [inline]
 __kmalloc_cache_noprof+0x26a/0x370 mm/slub.c:4357
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 fuse_folios_alloc fs/fuse/fuse_i.h:1082 [inline]
 fuse_writepage_args_alloc fs/fuse/file.c:2109 [inline]
 fuse_writepage_args_setup+0x165/0x9f0 fs/fuse/file.c:2157
 fuse_writepages_fill+0x310/0x1210 fs/fuse/file.c:2406
 write_cache_pages+0xd2/0x240 mm/page-writeback.c:2613
 fuse_writepages+0x2b7/0x4a0 fs/fuse/file.c:2467
 do_writepages+0x364/0x890 mm/page-writeback.c:2656
 __writeback_single_inode+0x14f/0x10d0 fs/fs-writeback.c:1680
 writeback_sb_inodes+0x822/0x1360 fs/fs-writeback.c:1976
 __writeback_inodes_wb+0x11b/0x260 fs/fs-writeback.c:2047
page last free pid 15 tgid 15 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1262 [inline]
 __free_frozen_pages+0xddf/0x10a0 mm/page_alloc.c:2680
 pagetable_free include/linux/mm.h:3002 [inline]
 pagetable_dtor_free include/linux/mm.h:3100 [inline]
 __tlb_remove_table+0x36b/0x460 include/asm-generic/tlb.h:215
 __tlb_remove_table_free mm/mmu_gather.c:227 [inline]
 tlb_remove_table_rcu+0x79/0xf0 mm/mmu_gather.c:290
 rcu_do_batch kernel/rcu/tree.c:2568 [inline]
 rcu_core+0xaac/0x17a0 kernel/rcu/tree.c:2824
 handle_softirqs+0x2d6/0x9b0 kernel/softirq.c:579
 run_ksoftirqd+0xcf/0x130 kernel/softirq.c:968
 smpboot_thread_fn+0x576/0xaa0 kernel/smpboot.c:164
 kthread+0x7b7/0x940 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Memory state around the buggy address:
 ffff888031b9d600: fa fb fc fc fa fb fc fc fa fb fc fc 00 00 fc fc
 ffff888031b9d680: 00 00 fc fc fa fb fc fc 00 00 fc fc 00 00 fc fc
>ffff888031b9d700: 00 00 fc fc 00 00 fc fc fa fb fc fc fa fb fc fc
                            ^
 ffff888031b9d780: 00 00 fc fc 00 00 fc fc fa fb fc fc 00 00 fc fc
 ffff888031b9d800: 00 06 fc fc fa fb fc fc fa fb fc fc fa fb fc fc
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