KASAN: slab-use-after-free Read in vidtv_psi_eit_event_destroy

Status: fixed on 2026/01/07 12:29
Subsystems: media
[Documentation on labels]
Reported-by: syzbot+1d9c0edea5907af239e0@syzkaller.appspotmail.com
Fix commit: 98aabfe2d79f media: vidtv: initialize local pointers upon transfer of memory ownership
First crash: 370d, last: 370d
▶ ▼ Discussions (4)
Title Replies (including bot) Last reply
[PATCH v3] media: vidtv: initialize local pointers upon transfer of memory ownership 2 (2) 2025/09/05 12:53
[PATCH v2 RESEND] media: vidtv: initialize local pointers upon transfer of memory ownership 2 (2) 2025/09/04 19:09
[PATCH v2] media: vidtv: initialize local pointers upon transfer of memory ownership 2 (2) 2025/08/23 14:33
[PATCH] media: vidtv: fix to initialize local pointers upon transfer of memory ownership 4 (4) 2025/08/22 15:35

Sample crash report:
RDX: 0010000000000402 RSI: 0000000000006f29 RDI: 0000000000000003
RBP: 00007f00d9410d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f00d95b5fa0 R15: 00007fffd52cb458
 </TASK>
==================================================================
BUG: KASAN: slab-use-after-free in vidtv_psi_eit_event_destroy+0xe9/0x100 drivers/media/test-drivers/vidtv/vidtv_psi.c:2043
Read of size 8 at addr ffff888032a8af54 by task syz.1.86/6421

CPU: 1 UID: 0 PID: 6421 Comm: syz.1.86 Not tainted 6.16.0-syzkaller-00857-gced1b9e0392d #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <TASK>
 __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
 vidtv_psi_eit_event_destroy+0xe9/0x100 drivers/media/test-drivers/vidtv/vidtv_psi.c:2043
 vidtv_channel_si_init+0x15cd/0x1a50 drivers/media/test-drivers/vidtv/vidtv_channel.c:491
 vidtv_mux_init+0x526/0xbe0 drivers/media/test-drivers/vidtv/vidtv_mux.c:519
 vidtv_start_streaming drivers/media/test-drivers/vidtv/vidtv_bridge.c:194 [inline]
 vidtv_start_feed+0x33e/0x4d0 drivers/media/test-drivers/vidtv/vidtv_bridge.c:239
 dmx_section_feed_start_filtering+0x3a8/0x660 drivers/media/dvb-core/dvb_demux.c:973
 dvb_dmxdev_filter_start+0x785/0xe10 drivers/media/dvb-core/dmxdev.c:757
 dvb_demux_do_ioctl+0xa63/0x12f0 drivers/media/dvb-core/dmxdev.c:1050
 dvb_usercopy+0x164/0x340 drivers/media/dvb-core/dvbdev.c:999
 dvb_demux_ioctl+0x29/0x40 drivers/media/dvb-core/dmxdev.c:1186
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:598 [inline]
 __se_sys_ioctl fs/ioctl.c:584 [inline]
 __x64_sys_ioctl+0x18b/0x210 fs/ioctl.c:584
 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: 0033:0x7f00d938e9a9
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:00007f00da241038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f00d95b5fa0 RCX: 00007f00d938e9a9
RDX: 0010000000000402 RSI: 0000000000006f29 RDI: 0000000000000003
RBP: 00007f00d9410d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f00d95b5fa0 R15: 00007fffd52cb458
 </TASK>

Allocated by task 6421:
 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:377 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 vidtv_psi_eit_event_init+0xe0/0x3f0 drivers/media/test-drivers/vidtv/vidtv_psi.c:1985
 vidtv_channel_eit_event_cat_into_new drivers/media/test-drivers/vidtv/vidtv_channel.c:182 [inline]
 vidtv_channel_si_init+0x897/0x1a50 drivers/media/test-drivers/vidtv/vidtv_channel.c:439
 vidtv_mux_init+0x526/0xbe0 drivers/media/test-drivers/vidtv/vidtv_mux.c:519
 vidtv_start_streaming drivers/media/test-drivers/vidtv/vidtv_bridge.c:194 [inline]
 vidtv_start_feed+0x33e/0x4d0 drivers/media/test-drivers/vidtv/vidtv_bridge.c:239
 dmx_section_feed_start_filtering+0x3a8/0x660 drivers/media/dvb-core/dvb_demux.c:973
 dvb_dmxdev_filter_start+0x785/0xe10 drivers/media/dvb-core/dmxdev.c:757
 dvb_demux_do_ioctl+0xa63/0x12f0 drivers/media/dvb-core/dmxdev.c:1050
 dvb_usercopy+0x164/0x340 drivers/media/dvb-core/dvbdev.c:999
 dvb_demux_ioctl+0x29/0x40 drivers/media/dvb-core/dmxdev.c:1186
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:598 [inline]
 __se_sys_ioctl fs/ioctl.c:584 [inline]
 __x64_sys_ioctl+0x18b/0x210 fs/ioctl.c:584
 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 6421:
 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:247 [inline]
 __kasan_slab_free+0x51/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2381 [inline]
 slab_free mm/slub.c:4643 [inline]
 kfree+0x2b4/0x4d0 mm/slub.c:4842
 vidtv_psi_eit_event_destroy drivers/media/test-drivers/vidtv/vidtv_psi.c:2045 [inline]
 vidtv_psi_eit_table_destroy+0x133/0x180 drivers/media/test-drivers/vidtv/vidtv_psi.c:2051
 vidtv_channel_si_init+0x163d/0x1a50 drivers/media/test-drivers/vidtv/vidtv_channel.c:485
 vidtv_mux_init+0x526/0xbe0 drivers/media/test-drivers/vidtv/vidtv_mux.c:519
 vidtv_start_streaming drivers/media/test-drivers/vidtv/vidtv_bridge.c:194 [inline]
 vidtv_start_feed+0x33e/0x4d0 drivers/media/test-drivers/vidtv/vidtv_bridge.c:239
 dmx_section_feed_start_filtering+0x3a8/0x660 drivers/media/dvb-core/dvb_demux.c:973
 dvb_dmxdev_filter_start+0x785/0xe10 drivers/media/dvb-core/dmxdev.c:757
 dvb_demux_do_ioctl+0xa63/0x12f0 drivers/media/dvb-core/dmxdev.c:1050
 dvb_usercopy+0x164/0x340 drivers/media/dvb-core/dvbdev.c:999
 dvb_demux_ioctl+0x29/0x40 drivers/media/dvb-core/dmxdev.c:1186
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:598 [inline]
 __se_sys_ioctl fs/ioctl.c:584 [inline]
 __x64_sys_ioctl+0x18b/0x210 fs/ioctl.c:584
 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

The buggy address belongs to the object at ffff888032a8af40
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 20 bytes inside of
 freed 32-byte region [ffff888032a8af40, ffff888032a8af60)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x32a8a
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000000 ffff88801b841780 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000400040 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 0x52800(GFP_NOWAIT|__GFP_NORETRY|__GFP_COMP), pid 5565, tgid 5565 (dhcpcd-run-hook), ts 67368240986, free_ts 67310237145
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1704
 prep_new_page mm/page_alloc.c:1712 [inline]
 get_page_from_freelist+0x1321/0x3890 mm/page_alloc.c:3669
 __alloc_frozen_pages_noprof+0x261/0x23f0 mm/page_alloc.c:4959
 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2419
 alloc_slab_page mm/slub.c:2451 [inline]
 allocate_slab mm/slub.c:2619 [inline]
 new_slab+0x23b/0x330 mm/slub.c:2673
 ___slab_alloc+0xd9c/0x1940 mm/slub.c:3859
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3949
 __slab_alloc_node mm/slub.c:4024 [inline]
 slab_alloc_node mm/slub.c:4185 [inline]
 __kmalloc_cache_noprof+0xfb/0x3e0 mm/slub.c:4354
 kmalloc_noprof include/linux/slab.h:905 [inline]
 slab_free_hook mm/slub.c:2333 [inline]
 slab_free mm/slub.c:4643 [inline]
 kmem_cache_free+0x142/0x4d0 mm/slub.c:4745
 vms_complete_munmap_vmas+0x573/0x970 mm/vma.c:1288
 __mmap_complete mm/vma.c:2519 [inline]
 __mmap_region+0x8e7/0x25e0 mm/vma.c:2630
 mmap_region+0x1ab/0x3f0 mm/vma.c:2692
 do_mmap+0xa3e/0x1210 mm/mmap.c:561
 vm_mmap_pgoff+0x281/0x450 mm/util.c:579
 ksys_mmap_pgoff+0x32c/0x5c0 mm/mmap.c:607
 __do_sys_mmap arch/x86/kernel/sys_x86_64.c:89 [inline]
 __se_sys_mmap arch/x86/kernel/sys_x86_64.c:82 [inline]
 __x64_sys_mmap+0x125/0x190 arch/x86/kernel/sys_x86_64.c:82
page last free pid 0 tgid 0 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1248 [inline]
 __free_frozen_pages+0x7fe/0x1180 mm/page_alloc.c:2706
 pagetable_free include/linux/mm.h:2884 [inline]
 pagetable_dtor_free include/linux/mm.h:2982 [inline]
 __tlb_remove_table include/asm-generic/tlb.h:220 [inline]
 __tlb_remove_table_free mm/mmu_gather.c:227 [inline]
 tlb_remove_table_rcu+0x116/0x1a0 mm/mmu_gather.c:290
 rcu_do_batch kernel/rcu/tree.c:2576 [inline]
 rcu_core+0x799/0x14e0 kernel/rcu/tree.c:2832
 handle_softirqs+0x216/0x8e0 kernel/softirq.c:579
 __do_softirq kernel/softirq.c:613 [inline]
 invoke_softirq kernel/softirq.c:453 [inline]
 __irq_exit_rcu+0x109/0x170 kernel/softirq.c:680
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1050
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702

Memory state around the buggy address:
 ffff888032a8ae00: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
 ffff888032a8ae80: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
>ffff888032a8af00: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
                                                 ^
 ffff888032a8af80: 00 00 00 05 fc fc fc fc 00 00 05 fc fc fc fc fc
 ffff888032a8b000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/07/30 05:17 upstream ced1b9e0392d f8f2b4da .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: slab-use-after-free Read in vidtv_psi_eit_event_destroy
2025/07/30 00:14 upstream ced1b9e0392d ba28e0a8 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: slab-use-after-free Read in vidtv_psi_eit_event_destroy
* Struck through repros no longer work on HEAD.