================================================================== BUG: KASAN: use-after-free in process_notifier+0x343/0x7b0 drivers/misc/uid_sys_stats.c:707 Write of size 8 at addr ffff888153f12158 by task syz-executor.2/5296 CPU: 1 PID: 5296 Comm: syz-executor.2 Not tainted 6.1.25-syzkaller-00087-ge0c4636bd239 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x151/0x1b7 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:316 [inline] print_report+0x158/0x4e0 mm/kasan/report.c:427 kasan_report+0x13c/0x170 mm/kasan/report.c:531 __asan_report_store8_noabort+0x17/0x20 mm/kasan/report_generic.c:356 process_notifier+0x343/0x7b0 drivers/misc/uid_sys_stats.c:707 notifier_call_chain kernel/notifier.c:87 [inline] blocking_notifier_call_chain+0xbb/0x140 kernel/notifier.c:382 profile_task_exit+0x1e/0x30 kernel/profile.c:146 do_exit+0x2c1/0x2b80 kernel/exit.c:819 do_group_exit+0x21a/0x2d0 kernel/exit.c:1025 get_signal+0x169d/0x1820 kernel/signal.c:2866 arch_do_signal_or_restart+0xb0/0x16f0 arch/x86/kernel/signal.c:869 exit_to_user_mode_loop+0x6b/0xa0 kernel/entry/common.c:168 exit_to_user_mode_prepare+0x5a/0xa0 kernel/entry/common.c:204 __syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline] syscall_exit_to_user_mode+0x26/0x130 kernel/entry/common.c:297 do_syscall_64+0x49/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f89776a7ef5 Code: 24 0c 89 3c 24 48 89 4c 24 18 e8 f6 b9 ff ff 4c 8b 54 24 18 48 8b 54 24 10 41 89 c0 8b 74 24 0c 8b 3c 24 b8 e6 00 00 00 0f 05 <44> 89 c7 48 89 04 24 e8 4f ba ff ff 48 8b 04 24 48 83 c4 28 f7 d8 RSP: 002b:00007f8978375010 EFLAGS: 00000293 ORIG_RAX: 00000000000000e6 RAX: fffffffffffffdfc RBX: 00007f897779bf80 RCX: 00007f89776a7ef5 RDX: 00007f8978375050 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f89776c847a R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000 R13: 000000000000000b R14: 00007f897779bf80 R15: 00007ffff49b8278 Allocated by task 5296: kasan_save_stack mm/kasan/common.c:45 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:52 kasan_save_alloc_info+0x1f/0x30 mm/kasan/generic.c:505 ____kasan_kmalloc mm/kasan/common.c:379 [inline] __kasan_kmalloc+0x9c/0xb0 mm/kasan/common.c:388 kasan_kmalloc include/linux/kasan.h:212 [inline] kmalloc_trace+0x44/0xa0 mm/slab_common.c:1052 kmalloc include/linux/slab.h:553 [inline] process_notifier+0x2c1/0x7b0 drivers/misc/uid_sys_stats.c:695 notifier_call_chain kernel/notifier.c:87 [inline] blocking_notifier_call_chain+0xbb/0x140 kernel/notifier.c:382 profile_task_exit+0x1e/0x30 kernel/profile.c:146 do_exit+0x2c1/0x2b80 kernel/exit.c:819 do_group_exit+0x21a/0x2d0 kernel/exit.c:1025 get_signal+0x169d/0x1820 kernel/signal.c:2866 arch_do_signal_or_restart+0xb0/0x16f0 arch/x86/kernel/signal.c:869 exit_to_user_mode_loop+0x6b/0xa0 kernel/entry/common.c:168 exit_to_user_mode_prepare+0x5a/0xa0 kernel/entry/common.c:204 __syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline] syscall_exit_to_user_mode+0x26/0x130 kernel/entry/common.c:297 do_syscall_64+0x49/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x63/0xcd Freed by task 377: kasan_save_stack mm/kasan/common.c:45 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:52 kasan_save_free_info+0x2b/0x40 mm/kasan/generic.c:516 ____kasan_slab_free+0x131/0x180 mm/kasan/common.c:241 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:249 kasan_slab_free include/linux/kasan.h:178 [inline] slab_free_hook mm/slub.c:1744 [inline] slab_free_freelist_hook mm/slub.c:1770 [inline] slab_free mm/slub.c:3681 [inline] __kmem_cache_free+0x218/0x3b0 mm/slub.c:3694 kfree+0x7a/0xf0 mm/slab_common.c:1009 update_stats_workfn+0x36b/0x3e0 drivers/misc/uid_sys_stats.c:674 process_one_work+0x73d/0xcb0 kernel/workqueue.c:2296 worker_thread+0xa60/0x1260 kernel/workqueue.c:2443 kthread+0x26d/0x300 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 The buggy address belongs to the object at ffff888153f12100 which belongs to the cache kmalloc-96 of size 96 The buggy address is located 88 bytes inside of 96-byte region [ffff888153f12100, ffff888153f12160) The buggy address belongs to the physical page: page:ffffea00054fc480 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x153f12 flags: 0x4000000000000200(slab|zone=1) raw: 4000000000000200 0000000000000000 dead000000000122 ffff888100042900 raw: 0000000000000000 0000000080200020 00000001ffffffff 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 0x112c40(GFP_NOFS|__GFP_NOWARN|__GFP_NORETRY|__GFP_HARDWALL), pid 1131, tgid 1131 (syz-executor.5), ts 1541149405916, free_ts 1541149303938 set_page_owner include/linux/page_owner.h:33 [inline] post_alloc_hook+0x213/0x220 mm/page_alloc.c:2582 prep_new_page+0x1b/0x110 mm/page_alloc.c:2589 get_page_from_freelist+0x2762/0x27f0 mm/page_alloc.c:4387 __alloc_pages+0x3a1/0x780 mm/page_alloc.c:5664 allocate_slab mm/slub.c:1959 [inline] new_slab+0xce/0x4c0 mm/slub.c:2012 ___slab_alloc+0x6f9/0xb80 mm/slub.c:3200 __slab_alloc+0x5d/0xa0 mm/slub.c:3299 slab_alloc_node mm/slub.c:3384 [inline] __kmem_cache_alloc_node+0x1af/0x250 mm/slub.c:3457 __do_kmalloc_node mm/slab_common.c:956 [inline] __kmalloc+0xa3/0x1e0 mm/slab_common.c:970 kmalloc_array include/linux/slab.h:605 [inline] kcalloc include/linux/slab.h:636 [inline] ext4_find_extent+0x370/0xdb0 fs/ext4/extents.c:914 ext4_ext_map_blocks+0x255/0x71e0 fs/ext4/extents.c:4103 ext4_map_blocks+0xa42/0x1ce0 fs/ext4/inode.c:651 ext4_getblk+0x1eb/0x7b0 fs/ext4/inode.c:864 ext4_bread+0x2f/0x180 fs/ext4/inode.c:920 ext4_append+0x31f/0x5b0 fs/ext4/namei.c:83 ext4_init_new_dir+0x33f/0x620 fs/ext4/namei.c:2955 page last free stack trace: reset_page_owner include/linux/page_owner.h:26 [inline] free_pages_prepare mm/page_alloc.c:1494 [inline] free_pcp_prepare mm/page_alloc.c:1568 [inline] free_unref_page_prepare+0x83d/0x850 mm/page_alloc.c:3486 free_unref_page+0x8d/0x480 mm/page_alloc.c:3582 free_the_page mm/page_alloc.c:794 [inline] __free_pages+0x61/0xf0 mm/page_alloc.c:5753 free_pages+0x7c/0x90 mm/page_alloc.c:5764 _pgd_free arch/x86/mm/pgtable.c:420 [inline] pgd_free+0x17d/0x190 arch/x86/mm/pgtable.c:476 mm_free_pgd kernel/fork.c:814 [inline] __mmdrop+0xb0/0x3e0 kernel/fork.c:865 mmdrop include/linux/sched/mm.h:50 [inline] mmdrop_sched include/linux/sched/mm.h:78 [inline] finish_task_switch+0x2cd/0x7b0 kernel/sched/core.c:5249 context_switch kernel/sched/core.c:5350 [inline] __schedule+0xca1/0x1540 kernel/sched/core.c:6673 schedule+0xc3/0x180 kernel/sched/core.c:6749 jbd2_log_wait_commit+0x197/0x360 fs/jbd2/journal.c:709 __jbd2_journal_force_commit+0x163/0x1e0 fs/jbd2/journal.c:558 jbd2_journal_force_commit_nested+0x15/0x30 fs/jbd2/journal.c:579 ext4_should_retry_alloc+0x173/0x2d0 fs/ext4/balloc.c:670 ext4_mkdir+0xaae/0xce0 fs/ext4/namei.c:3034 vfs_mkdir+0x398/0x570 fs/namei.c:4036 do_mkdirat+0x1eb/0x450 fs/namei.c:4061 Memory state around the buggy address: ffff888153f12000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888153f12080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888153f12100: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ^ ffff888153f12180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888153f12200: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ==================================================================