================================================================== BUG: KASAN: slab-use-after-free in dvb_device_open+0x33f/0x3b0 drivers/media/dvb-core/dvbdev.c:99 Read of size 8 at addr ffff88802fc9e818 by task syz.1.2010/12954 CPU: 1 UID: 0 PID: 12954 Comm: syz.1.2010 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x156/0x4c9 mm/kasan/report.c:482 kasan_report+0xdf/0x1e0 mm/kasan/report.c:595 dvb_device_open+0x33f/0x3b0 drivers/media/dvb-core/dvbdev.c:99 chrdev_open+0x234/0x6a0 fs/char_dev.c:411 do_dentry_open+0x6d8/0x1660 fs/open.c:949 vfs_open+0x82/0x3f0 fs/open.c:1081 do_open fs/namei.c:4671 [inline] path_openat+0x208c/0x31a0 fs/namei.c:4830 do_file_open+0x20e/0x430 fs/namei.c:4859 do_sys_openat2+0x10d/0x1e0 fs/open.c:1366 do_sys_open fs/open.c:1372 [inline] __do_sys_openat fs/open.c:1388 [inline] __se_sys_openat fs/open.c:1383 [inline] __x64_sys_openat+0x12d/0x210 fs/open.c:1383 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f7eaad5cfce Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08 RSP: 002b:00007f7eabc7fb28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f7eabc806c0 RCX: 00007f7eaad5cfce RDX: 0000000000000002 RSI: 00007f7eabc7fc00 RDI: ffffffffffffff9c RBP: 00007f7eabc7fc00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd R13: 00007f7eab016038 R14: 00007f7eab015fa0 R15: 00007fff22e6cac8 Allocated by task 12792: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5238 [inline] __kmalloc_noprof+0x301/0x850 mm/slub.c:5250 kmalloc_noprof include/linux/slab.h:954 [inline] io_cache_alloc_new+0x45/0xe0 io_uring/alloc_cache.c:40 io_cache_alloc io_uring/alloc_cache.h:61 [inline] io_uring_alloc_async_data io_uring/io_uring.h:341 [inline] io_rw_alloc_async io_uring/rw.c:209 [inline] __io_prep_rw+0x21d/0xfa0 io_uring/rw.c:268 io_prep_rw+0x76/0x2c0 io_uring/rw.c:328 io_prep_rwv io_uring/rw.c:350 [inline] io_prep_readv+0x20/0xa0 io_uring/rw.c:365 io_init_req io_uring/io_uring.c:1828 [inline] io_submit_sqe io_uring/io_uring.c:1875 [inline] io_submit_sqes+0x99b/0x22f0 io_uring/io_uring.c:2043 __do_sys_io_uring_enter+0x9c0/0x1a20 io_uring/io_uring.c:2603 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 12792: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2692 [inline] slab_free mm/slub.c:6143 [inline] kfree+0x1f6/0x6b0 mm/slub.c:6461 io_clean_op io_uring/io_uring.c:323 [inline] io_free_batch_list io_uring/io_uring.c:1109 [inline] __io_submit_flush_completions+0x13f5/0x1910 io_uring/io_uring.c:1147 io_submit_flush_completions io_uring/io_uring.h:238 [inline] ctx_flush_and_put.isra.0+0x92/0x160 io_uring/tw.c:43 io_handle_tw_list+0x419/0x580 io_uring/tw.c:84 tctx_task_work_run+0x57/0x340 io_uring/tw.c:132 tctx_task_work+0x7a/0xd0 io_uring/tw.c:150 task_work_run+0x150/0x240 kernel/task_work.c:233 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x829/0x2aa0 kernel/exit.c:971 do_group_exit+0xd5/0x2a0 kernel/exit.c:1112 get_signal+0x1ec7/0x21e0 kernel/signal.c:3034 arch_do_signal_or_restart+0x91/0x7a0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline] exit_to_user_mode_loop+0x86/0x4a0 kernel/entry/common.c:98 __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 include/linux/entry-common.h:325 [inline] do_syscall_64+0x67c/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88802fc9e800 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 24 bytes inside of freed 256-byte region [ffff88802fc9e800, ffff88802fc9e900) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88802fc9e800 pfn:0x2fc9e head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000240(workingset|head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000240 ffff88801b842b40 ffffea0000a26e10 ffffea0000daa890 raw: ffff88802fc9e800 000000080010000f 00000000f5000000 0000000000000000 head: 00fff00000000240 ffff88801b842b40 ffffea0000a26e10 ffffea0000daa890 head: ffff88802fc9e800 000000080010000f 00000000f5000000 0000000000000000 head: 00fff00000000001 ffffea0000bf2781 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 20043408069, free_ts 0 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x153/0x170 mm/page_alloc.c:1889 prep_new_page mm/page_alloc.c:1897 [inline] get_page_from_freelist+0x111d/0x3140 mm/page_alloc.c:3962 __alloc_frozen_pages_noprof+0x27c/0x2ba0 mm/page_alloc.c:5250 alloc_slab_page mm/slub.c:3269 [inline] allocate_slab mm/slub.c:3458 [inline] new_slab+0xa6/0x6d0 mm/slub.c:3516 refill_objects+0x26b/0x400 mm/slub.c:7153 refill_sheaf mm/slub.c:2818 [inline] alloc_full_sheaf mm/slub.c:2839 [inline] __pcs_replace_empty_main+0x19f/0x600 mm/slub.c:4602 alloc_from_pcs mm/slub.c:4695 [inline] slab_alloc_node mm/slub.c:4829 [inline] __kmalloc_cache_noprof+0x493/0x6f0 mm/slub.c:5353 kmalloc_noprof include/linux/slab.h:950 [inline] kzalloc_noprof include/linux/slab.h:1188 [inline] bus_add_driver+0x92/0x5b0 drivers/base/bus.c:699 driver_register+0x1e2/0x360 drivers/base/driver.c:249 usb_register_driver drivers/usb/core/driver.c:1078 [inline] usb_register_driver+0x21c/0x3e0 drivers/usb/core/driver.c:1060 pvr_init+0xa1/0x130 drivers/media/usb/pvrusb2/pvrusb2-main.c:112 do_one_initcall+0x11d/0x760 init/main.c:1382 do_initcall_level init/main.c:1444 [inline] do_initcalls init/main.c:1460 [inline] do_basic_setup init/main.c:1479 [inline] kernel_init_freeable+0x6e5/0x7a0 init/main.c:1692 kernel_init+0x1f/0x1e0 init/main.c:1582 ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158 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: ffff88802fc9e700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88802fc9e780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88802fc9e800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88802fc9e880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88802fc9e900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================