================================================================== BUG: KASAN: slab-use-after-free in dvb_device_open+0x36a/0x3b0 drivers/media/dvb-core/dvbdev.c:99 Read of size 8 at addr ffff888144af4818 by task syz.1.1848/12008 CPU: 1 UID: 0 PID: 12008 Comm: syz.1.1848 Tainted: GF R 6.16.0-syzkaller-11895-gcca7a0aae895 #0 PREEMPT(full) Tainted: [F]=FORCED_MODULE, [R]=FORCED_RMMOD Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xcd/0x630 mm/kasan/report.c:482 kasan_report+0xe0/0x110 mm/kasan/report.c:595 dvb_device_open+0x36a/0x3b0 drivers/media/dvb-core/dvbdev.c:99 chrdev_open+0x231/0x6a0 fs/char_dev.c:414 do_dentry_open+0x97f/0x1530 fs/open.c:965 vfs_open+0x82/0x3f0 fs/open.c:1095 do_open fs/namei.c:3887 [inline] path_openat+0x1de4/0x2cb0 fs/namei.c:4046 do_filp_open+0x20b/0x470 fs/namei.c:4073 do_sys_openat2+0x11b/0x1d0 fs/open.c:1435 do_sys_open fs/open.c:1450 [inline] __do_sys_openat fs/open.c:1466 [inline] __se_sys_openat fs/open.c:1461 [inline] __x64_sys_openat+0x174/0x210 fs/open.c:1461 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x490 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f7dffb8ebe9 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:00007f7dfddf6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f7dffdb5fa0 RCX: 00007f7dffb8ebe9 RDX: 0000000000000001 RSI: 0000200000000000 RDI: ffffffffffffff9c RBP: 00007f7dffc11e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f7dffdb6038 R14: 00007f7dffdb5fa0 R15: 00007ffe6fb40b78 Allocated by task 11889: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:388 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:405 kasan_kmalloc include/linux/kasan.h:260 [inline] __do_kmalloc_node mm/slub.c:4365 [inline] __kvmalloc_node_noprof+0x27b/0x620 mm/slub.c:5052 kvmalloc_array_node_noprof include/linux/slab.h:1065 [inline] io_alloc_cache_init+0x33/0x170 io_uring/alloc_cache.c:25 io_ring_ctx_alloc io_uring/io_uring.c:343 [inline] io_uring_create io_uring/io_uring.c:3743 [inline] io_uring_setup+0x680/0x2080 io_uring/io_uring.c:3890 __do_sys_io_uring_setup io_uring/io_uring.c:3924 [inline] __se_sys_io_uring_setup io_uring/io_uring.c:3915 [inline] __x64_sys_io_uring_setup+0xc2/0x170 io_uring/io_uring.c:3915 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x490 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 13: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:243 [inline] __kasan_slab_free+0x60/0x70 mm/kasan/common.c:275 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2417 [inline] slab_free mm/slub.c:4680 [inline] kfree+0x2b4/0x4d0 mm/slub.c:4879 io_alloc_cache_free+0x1eb/0x2e0 io_uring/alloc_cache.c:16 io_free_alloc_caches+0x70/0x80 io_uring/io_uring.c:294 io_ring_ctx_free io_uring/io_uring.c:2794 [inline] io_ring_exit_work+0x7d8/0x10a0 io_uring/io_uring.c:3031 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3236 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x5d7/0x6f0 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 ffff888144af4800 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 24 bytes inside of freed 256-byte region [ffff888144af4800, ffff888144af4900) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x144af4 head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 anon flags: 0x57ff00000000040(head|node=1|zone=2|lastcpupid=0x7ff) page_type: f5(slab) raw: 057ff00000000040 ffff88801b841b40 ffffea0001f39b00 0000000000000005 raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 057ff00000000040 ffff88801b841b40 ffffea0001f39b00 0000000000000005 head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 057ff00000000001 ffffea000512bd01 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000002 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 27358859676, free_ts 0 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1851 prep_new_page mm/page_alloc.c:1859 [inline] get_page_from_freelist+0x132b/0x38e0 mm/page_alloc.c:3858 __alloc_frozen_pages_noprof+0x261/0x23f0 mm/page_alloc.c:5148 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2416 alloc_slab_page mm/slub.c:2487 [inline] allocate_slab mm/slub.c:2655 [inline] new_slab+0x247/0x330 mm/slub.c:2709 ___slab_alloc+0xcf2/0x1740 mm/slub.c:3891 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3981 __slab_alloc_node mm/slub.c:4056 [inline] slab_alloc_node mm/slub.c:4217 [inline] __kmalloc_cache_noprof+0xfb/0x3e0 mm/slub.c:4391 kmalloc_noprof include/linux/slab.h:905 [inline] kzalloc_noprof include/linux/slab.h:1039 [inline] bus_add_driver+0x92/0x690 drivers/base/bus.c:662 driver_register+0x15c/0x4b0 drivers/base/driver.c:249 i2c_register_driver+0xd9/0x1c0 drivers/i2c/i2c-core-base.c:2022 do_one_initcall+0x120/0x6e0 init/main.c:1269 do_initcall_level init/main.c:1331 [inline] do_initcalls init/main.c:1347 [inline] do_basic_setup init/main.c:1366 [inline] kernel_init_freeable+0x5c2/0x910 init/main.c:1579 kernel_init+0x1c/0x2b0 init/main.c:1469 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 page_owner free stack trace missing Memory state around the buggy address: ffff888144af4700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888144af4780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888144af4800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888144af4880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888144af4900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================