================================================================== BUG: KASAN: use-after-free in process_notifier+0x343/0x7b0 drivers/misc/uid_sys_stats.c:707 Write of size 8 at addr ffff88815484cf58 by task syz-executor.1/30736 CPU: 1 PID: 30736 Comm: syz-executor.1 Tainted: G W 6.1.25-syzkaller-00062-gc603880bd51d #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: 0033:0x7fcf0447cae9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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:00007fcf051e4178 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007fcf0459c058 RCX: 00007fcf0447cae9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fcf0459c058 RBP: 00007fcf0459c050 R08: 00007fcf051e46c0 R09: 00007fcf051e46c0 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fcf0459c05c R13: 000000000000006e R14: 00007ffc001b8370 R15: 00007ffc001b8458 Allocated by task 30736: 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 819: 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 ffff88815484cf00 which belongs to the cache kmalloc-96 of size 96 The buggy address is located 88 bytes inside of 96-byte region [ffff88815484cf00, ffff88815484cf60) The buggy address belongs to the physical page: page:ffffea0005521300 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x15484c flags: 0x4000000000000200(slab|zone=1) raw: 4000000000000200 ffffea000612e0c0 dead000000000005 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 30100, tgid 30079 (syz-executor.0), ts 1544914732901, free_ts 1544840764554 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+0x40f/0x1ce0 fs/ext4/inode.c:576 ext4_mpage_readpages+0x8aa/0x1ec0 fs/ext4/readpage.c:301 ext4_read_folio+0x10a/0x240 fs/ext4/inode.c:3238 filemap_read_folio+0xfc/0x2a0 mm/filemap.c:2419 filemap_fault+0xc91/0x1160 mm/filemap.c:3233 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_list+0xf6/0x6c0 mm/page_alloc.c:3628 release_pages+0xf7f/0xfe0 mm/swap.c:1055 free_pages_and_swap_cache+0x8a/0xa0 mm/swap_state.c:314 tlb_batch_pages_flush mm/mmu_gather.c:59 [inline] tlb_flush_mmu_free mm/mmu_gather.c:254 [inline] tlb_flush_mmu mm/mmu_gather.c:261 [inline] tlb_finish_mmu+0x1e0/0x3f0 mm/mmu_gather.c:361 exit_mmap+0x3e5/0x8a0 mm/mmap.c:3329 __mmput+0x95/0x310 kernel/fork.c:1272 mmput+0x56/0x170 kernel/fork.c:1295 exit_mm kernel/exit.c:566 [inline] do_exit+0xb29/0x2b80 kernel/exit.c:862 __do_sys_exit kernel/exit.c:992 [inline] __se_sys_exit kernel/exit.c:990 [inline] __ia32_sys_exit+0x0/0x40 kernel/exit.c:990 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Memory state around the buggy address: ffff88815484ce00: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ffff88815484ce80: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc >ffff88815484cf00: fa fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ^ ffff88815484cf80: 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc ffff88815484d000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ==================================================================