================================================================== BUG: KASAN: slab-use-after-free in ptep_get include/linux/pgtable.h:340 [inline] BUG: KASAN: slab-use-after-free in filemap_map_folio_range mm/filemap.c:3666 [inline] BUG: KASAN: slab-use-after-free in filemap_map_pages+0xc95/0x1740 mm/filemap.c:3783 Read of size 8 at addr ffff888042f5d000 by task syz.4.1138/13469 CPU: 1 UID: 0 PID: 13469 Comm: syz.4.1138 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xca/0x240 mm/kasan/report.c:482 kasan_report+0x118/0x150 mm/kasan/report.c:595 ptep_get include/linux/pgtable.h:340 [inline] filemap_map_folio_range mm/filemap.c:3666 [inline] filemap_map_pages+0xc95/0x1740 mm/filemap.c:3783 do_fault_around mm/memory.c:5531 [inline] do_read_fault mm/memory.c:5564 [inline] do_fault mm/memory.c:5707 [inline] do_pte_missing mm/memory.c:4234 [inline] handle_pte_fault mm/memory.c:6052 [inline] __handle_mm_fault+0x34ac/0x5440 mm/memory.c:6195 handle_mm_fault+0x40a/0x8e0 mm/memory.c:6364 faultin_page mm/gup.c:1144 [inline] __get_user_pages+0x1699/0x2ce0 mm/gup.c:1446 populate_vma_page_range+0x29f/0x3a0 mm/gup.c:1880 __mm_populate+0x24c/0x380 mm/gup.c:1983 mm_populate include/linux/mm.h:3367 [inline] vm_mmap_pgoff+0x387/0x4d0 mm/util.c:585 ksys_mmap_pgoff+0x51f/0x760 mm/mmap.c:604 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fca3778ebe9 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fca386bc038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007fca379b6090 RCX: 00007fca3778ebe9 RDX: 00000000027ffff7 RSI: 0000000000600000 RDI: 0000200000000000 RBP: 00007fca37811e19 R08: 0000000000000004 R09: 0000000000000000 R10: 0000000004012011 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fca379b6128 R14: 00007fca379b6090 R15: 00007ffe3b560418 Allocated by task 5859: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 unpoison_slab_object mm/kasan/common.c:330 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:356 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4180 [inline] slab_alloc_node mm/slub.c:4229 [inline] kmem_cache_alloc_noprof+0x1c1/0x3c0 mm/slub.c:4236 mempool_alloc_noprof+0x1a7/0x510 mm/mempool.c:406 bio_alloc_bioset+0x241/0x1110 block/bio.c:555 bio_alloc include/linux/bio.h:372 [inline] submit_bh_wbc+0x22e/0x520 fs/buffer.c:2804 submit_bh fs/buffer.c:2829 [inline] __sync_dirty_buffer+0x22e/0x370 fs/buffer.c:2867 fat_set_state+0x272/0x350 fs/fat/inode.c:711 fat_put_super+0x48/0xb0 fs/fat/inode.c:737 generic_shutdown_super+0x135/0x2c0 fs/super.c:643 kill_block_super+0x44/0x90 fs/super.c:1766 deactivate_locked_super+0xbc/0x130 fs/super.c:474 cleanup_mnt+0x425/0x4c0 fs/namespace.c:1375 task_work_run+0x1d4/0x260 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop+0xec/0x110 kernel/entry/common.c:43 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 5856: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:243 [inline] __kasan_slab_free+0x5b/0x80 mm/kasan/common.c:275 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2417 [inline] slab_free_after_rcu_debug+0x129/0x2a0 mm/slub.c:4730 rcu_do_batch kernel/rcu/tree.c:2605 [inline] rcu_core+0xcab/0x1770 kernel/rcu/tree.c:2861 handle_softirqs+0x286/0x870 kernel/softirq.c:579 __do_softirq kernel/softirq.c:613 [inline] invoke_softirq kernel/softirq.c:453 [inline] __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1050 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 Last potentially related work creation: kasan_save_stack+0x3e/0x60 mm/kasan/common.c:47 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:548 slab_free_hook mm/slub.c:2378 [inline] slab_free mm/slub.c:4680 [inline] kmem_cache_free+0x2f6/0x400 mm/slub.c:4782 blk_update_request+0x57e/0xe60 block/blk-mq.c:989 blk_mq_end_request+0x3e/0x70 block/blk-mq.c:1151 blk_complete_reqs block/blk-mq.c:1226 [inline] blk_done_softirq+0x10a/0x160 block/blk-mq.c:1231 handle_softirqs+0x286/0x870 kernel/softirq.c:579 run_ksoftirqd+0x9b/0x100 kernel/softirq.c:968 smpboot_thread_fn+0x542/0xa60 kernel/smpboot.c:160 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 The buggy address belongs to the object at ffff888042f5d000 which belongs to the cache bio-200 of size 200 The buggy address is located 0 bytes inside of freed 200-byte region [ffff888042f5d000, ffff888042f5d0c8) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x42f5d flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000000 ffff888142ac1500 dead000000000122 0000000000000000 raw: 0000000000000000 00000000000c000c 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 0xd2800(GFP_NOWAIT|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5859, tgid 5859 (syz-executor), ts 875652436233, free_ts 875620838522 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1851 prep_new_page mm/page_alloc.c:1859 [inline] get_page_from_freelist+0x21e4/0x22c0 mm/page_alloc.c:3858 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5148 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2416 alloc_slab_page mm/slub.c:2487 [inline] allocate_slab+0x8a/0x370 mm/slub.c:2655 new_slab mm/slub.c:2709 [inline] ___slab_alloc+0xbeb/0x1410 mm/slub.c:3891 __slab_alloc mm/slub.c:3981 [inline] __slab_alloc_node mm/slub.c:4056 [inline] slab_alloc_node mm/slub.c:4217 [inline] kmem_cache_alloc_noprof+0x283/0x3c0 mm/slub.c:4236 mempool_alloc_noprof+0x1a7/0x510 mm/mempool.c:406 bio_alloc_bioset+0x241/0x1110 block/bio.c:555 bio_alloc include/linux/bio.h:372 [inline] submit_bh_wbc+0x22e/0x520 fs/buffer.c:2804 submit_bh fs/buffer.c:2829 [inline] __sync_dirty_buffer+0x22e/0x370 fs/buffer.c:2867 fat_set_state+0x272/0x350 fs/fat/inode.c:711 fat_put_super+0x48/0xb0 fs/fat/inode.c:737 generic_shutdown_super+0x135/0x2c0 fs/super.c:643 kill_block_super+0x44/0x90 fs/super.c:1766 deactivate_locked_super+0xbc/0x130 fs/super.c:474 page last free pid 6181 tgid 6181 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1395 [inline] __free_frozen_pages+0xbc4/0xd30 mm/page_alloc.c:2895 discard_slab mm/slub.c:2753 [inline] __put_partials+0x156/0x1a0 mm/slub.c:3218 put_cpu_partial+0x17c/0x250 mm/slub.c:3293 __slab_free+0x2d5/0x3c0 mm/slub.c:4550 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x97/0x140 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:340 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4180 [inline] slab_alloc_node mm/slub.c:4229 [inline] __do_kmalloc_node mm/slub.c:4364 [inline] __kmalloc_noprof+0x224/0x4f0 mm/slub.c:4377 kmalloc_noprof include/linux/slab.h:909 [inline] kmalloc_array_noprof include/linux/slab.h:948 [inline] lo_rw_aio+0x3fd/0xfa0 drivers/block/loop.c:359 do_req_filebacked drivers/block/loop.c:-1 [inline] loop_handle_cmd drivers/block/loop.c:1919 [inline] loop_process_work+0x835/0xf90 drivers/block/loop.c:1954 process_one_work kernel/workqueue.c:3236 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3319 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Memory state around the buggy address: ffff888042f5cf00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff888042f5cf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff888042f5d000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888042f5d080: fb fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc ffff888042f5d100: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb ==================================================================