================================================================== BUG: KASAN: slab-use-after-free in number+0xc48/0xf60 lib/vsprintf.c:572 Write of size 1 at addr ffff888012633a0e by task syz.0.0/5341 CPU: 0 UID: 0 PID: 5341 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: dump_stack_lvl+0xe8/0x150 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 number+0xc48/0xf60 lib/vsprintf.c:572 vsnprintf+0x8e5/0xee0 lib/vsprintf.c:2911 snprintf+0xda/0x120 lib/vsprintf.c:3041 media_request_alloc+0x319/0x5b0 drivers/media/mc/mc-request.c:320 media_device_request_alloc+0x98/0xd0 drivers/media/mc/mc-device.c:380 media_device_ioctl+0x278/0x430 drivers/media/mc/mc-device.c:465 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fc69818f7c9 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:00007fc6990ed038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fc6983e5fa0 RCX: 00007fc69818f7c9 RDX: 0000000000000000 RSI: 0000000080047c05 RDI: 0000000000000003 RBP: 00007fc698213f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fc6983e6038 R14: 00007fc6983e5fa0 R15: 00007ffca3559908 Allocated by task 5341: kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 poison_kmalloc_redzone mm/kasan/common.c:397 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:414 kasan_kmalloc include/linux/kasan.h:262 [inline] __kmalloc_cache_noprof+0x3e2/0x700 mm/slub.c:5776 kmalloc_noprof include/linux/slab.h:957 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] media_request_alloc+0xe4/0x5b0 drivers/media/mc/mc-request.c:294 media_device_request_alloc+0x98/0xd0 drivers/media/mc/mc-device.c:380 media_device_ioctl+0x278/0x430 drivers/media/mc/mc-device.c:465 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 5342: kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:252 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:284 kasan_slab_free include/linux/kasan.h:234 [inline] slab_free_hook mm/slub.c:2540 [inline] slab_free mm/slub.c:6670 [inline] kfree+0x1c0/0x660 mm/slub.c:6878 media_request_close+0x38/0x50 drivers/media/mc/mc-request.c:89 __fput+0x44c/0xa70 fs/file_table.c:468 task_work_run+0x1d4/0x260 kernel/task_work.c:233 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] __exit_to_user_mode_loop kernel/entry/common.c:44 [inline] exit_to_user_mode_loop+0xef/0x4e0 kernel/entry/common.c:75 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline] do_syscall_64+0x2b7/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888012633a00 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 14 bytes inside of freed 256-byte region [ffff888012633a00, ffff888012633b00) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x12633 flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000000 ffff88801a441b40 dead000000000122 0000000000000000 raw: 0000000000000000 0000000080080008 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 0x252800(GFP_NOWAIT|__GFP_NORETRY|__GFP_COMP|__GFP_THISNODE), pid 12, tgid 12 (kworker/u4:0), ts 85140860739, free_ts 83097091217 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x234/0x290 mm/page_alloc.c:1846 prep_new_page mm/page_alloc.c:1854 [inline] get_page_from_freelist+0x24e0/0x2580 mm/page_alloc.c:3915 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5210 alloc_slab_page mm/slub.c:3077 [inline] allocate_slab+0x7a/0x3b0 mm/slub.c:3248 new_slab mm/slub.c:3302 [inline] ___slab_alloc+0xe53/0x1820 mm/slub.c:4656 __slab_alloc+0x65/0x100 mm/slub.c:4779 __slab_alloc_node mm/slub.c:4855 [inline] slab_alloc_node mm/slub.c:5251 [inline] __do_kmalloc_node mm/slub.c:5656 [inline] __kmalloc_node_noprof+0x5d9/0x820 mm/slub.c:5663 kmalloc_array_node_noprof include/linux/slab.h:1075 [inline] alloc_slab_obj_exts+0x3e/0x100 mm/slub.c:2123 account_slab mm/slub.c:3202 [inline] allocate_slab+0x1cc/0x3b0 mm/slub.c:3267 new_slab mm/slub.c:3302 [inline] ___slab_alloc+0xe53/0x1820 mm/slub.c:4656 __slab_alloc+0x65/0x100 mm/slub.c:4779 __slab_alloc_node mm/slub.c:4855 [inline] slab_alloc_node mm/slub.c:5251 [inline] kmem_cache_alloc_noprof+0x40f/0x710 mm/slub.c:5270 node_alloc net/ipv6/ip6_fib.c:188 [inline] fib6_add_1+0x9c1/0x1460 net/ipv6/ip6_fib.c:-1 fib6_add+0x204/0x18a0 net/ipv6/ip6_fib.c:1444 __ip6_ins_rt net/ipv6/route.c:1351 [inline] ip6_ins_rt+0xc8/0x120 net/ipv6/route.c:1361 __ipv6_ifa_notify+0x62f/0xaa0 net/ipv6/addrconf.c:6283 page last free pid 78 tgid 78 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1395 [inline] free_unref_folios+0xdb3/0x14f0 mm/page_alloc.c:3000 shrink_folio_list+0x28df/0x5010 mm/vmscan.c:1534 evict_folios+0x473e/0x57f0 mm/vmscan.c:4711 try_to_shrink_lruvec+0x8a3/0xb50 mm/vmscan.c:4874 shrink_one+0x25c/0x720 mm/vmscan.c:4919 shrink_many mm/vmscan.c:4982 [inline] lru_gen_shrink_node mm/vmscan.c:5060 [inline] shrink_node+0x2f7d/0x35b0 mm/vmscan.c:6047 kswapd_shrink_node mm/vmscan.c:6901 [inline] balance_pgdat mm/vmscan.c:7084 [inline] kswapd+0x145a/0x2820 mm/vmscan.c:7354 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Memory state around the buggy address: ffff888012633900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888012633980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888012633a00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888012633a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888012633b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================