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BUG: KASAN: use-after-free in user_mode arch/x86/include/asm/ptrace.h:131 [inline]
BUG: KASAN: use-after-free in trace_page_fault_entries arch/x86/mm/fault.c:1516 [inline]
BUG: KASAN: use-after-free in do_page_fault+0x66/0x330 arch/x86/mm/fault.c:1528
Read of size 8 at addr ffff8881eae17ea0 by task syz-executor.0/423

CPU: 0 PID: 423 Comm: syz-executor.0 Not tainted 5.4.290-syzkaller-05053-g41adfeb3d639 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:

The buggy address belongs to the page:
page:ffffea0007ab85c0 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0x8000000000000000()
raw: 8000000000000000 0000000000000000 ffffea0007ab85c8 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC)
 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]
 kmem_cache_alloc_trace+0x12d/0x260 mm/slub.c:2854
 kmalloc include/linux/slab.h:556 [inline]
 kzalloc include/linux/slab.h:690 [inline]
 kobject_uevent_env+0x26f/0x710 lib/kobject_uevent.c:539
 kobject_synth_uevent+0x5fa/0xc60 lib/kobject_uevent.c:208
 store_uevent+0x12/0x20 kernel/module.c:1230
 module_attr_store+0x58/0x80 kernel/params.c:920
 kernfs_fop_write+0x2e2/0x3e0 fs/kernfs/file.c:315
 __vfs_write+0x103/0x750 fs/read_write.c:494
 vfs_write+0x206/0x4e0 fs/read_write.c:558
 ksys_write+0x199/0x2c0 fs/read_write.c:611
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_pages_ok+0x847/0x950 mm/page_alloc.c:1438
 free_the_page mm/page_alloc.c:4955 [inline]
 __free_pages+0x91/0x140 mm/page_alloc.c:4961
 __free_slab+0x221/0x2e0 mm/slub.c:1774
 free_slab mm/slub.c:1789 [inline]
 discard_slab mm/slub.c:1795 [inline]
 unfreeze_partials+0x14e/0x180 mm/slub.c:2288
 put_cpu_partial+0x44/0x180 mm/slub.c:2324
 __slab_free+0x297/0x360 mm/slub.c:2971
 qlist_free_all+0x43/0xb0 mm/kasan/quarantine.c:167
 quarantine_reduce+0x1d9/0x210 mm/kasan/quarantine.c:260
 __kasan_kmalloc+0x41/0x210 mm/kasan/common.c:507
 slab_post_alloc_hook mm/slab.h:584 [inline]
 slab_alloc_node mm/slub.c:2829 [inline]
 slab_alloc mm/slub.c:2837 [inline]
 kmem_cache_alloc+0xd9/0x250 mm/slub.c:2842
 getname_flags+0xb8/0x4e0 fs/namei.c:141
 user_path_at_empty+0x28/0x50 fs/namei.c:2703
 user_path_at include/linux/namei.h:49 [inline]
 ksys_chdir+0xa7/0x1f0 fs/open.c:459
 __do_sys_chdir fs/open.c:481 [inline]
 __se_sys_chdir fs/open.c:479 [inline]
 __x64_sys_chdir+0x34/0x40 fs/open.c:479
 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1

Memory state around the buggy address:
 ffff8881eae17d80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8881eae17e00: ff ff ff ff 00 00 00 00 00 00 00 00 ff ff ff ff
>ffff8881eae17e80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                               ^
 ffff8881eae17f00: f1 f1 f1 f1 00 f2 f2 f2 04 f3 f3 f3 ff ff ff ff
 ffff8881eae17f80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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