KASAN: slab-use-after-free Read in dvb_frontend_release (2)

Status: auto-obsoleted due to no activity on 2025/11/21 10:00
Subsystems: media
[Documentation on labels]
Reported-by: syzbot+a3400cacf1015dd75812@syzkaller.appspotmail.com
First crash: 348d, last: 348d
▶ ▼ Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.6 KASAN: slab-use-after-free Read in dvb_frontend_release origin:upstream 19 syz, C error 4 71d 179d 0/2 upstream: reported C repro on 2026/02/09 03:58
upstream KASAN: slab-use-after-free Read in dvb_frontend_release media 19 2 473d 481d 0/29 auto-obsoleted due to no activity on 2025/07/20 03:14
upstream KASAN: slab-use-after-free Read in dvb_frontend_release (3) prio:high media 19 syz, C error 252 3h50m 173d 0/29 upstream: reported C repro on 2026/02/14 12:34
linux-5.15 KASAN: use-after-free Read in dvb_frontend_release origin:upstream 19 syz, C error 6 5d10h 157d 0/3 upstream: reported C repro on 2026/03/02 23:20
linux-6.1 KASAN: use-after-free Read in dvb_frontend_release origin:lts-only 19 syz, C error 14 32d 150d 0/3 upstream: reported C repro on 2026/03/09 12:55

Sample crash report:
==================================================================
BUG: KASAN: slab-use-after-free in dvb_frontend_release+0x4ca/0x5b0 drivers/media/dvb-core/dvb_frontend.c:2916
Read of size 4 at addr ffff888029c1763c by task syz.3.23/6068

CPU: 1 UID: 0 PID: 6068 Comm: syz.3.23 Not tainted syzkaller #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
 dvb_frontend_release+0x4ca/0x5b0 drivers/media/dvb-core/dvb_frontend.c:2916
 __fput+0x3ff/0xb70 fs/file_table.c:468
 task_work_run+0x14d/0x240 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop+0xeb/0x110 kernel/entry/common.c:43
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 do_syscall_64+0x3f6/0x490 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fdc0eb8ebe9
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:00007ffc9089fad8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007fdc0edb7da0 RCX: 00007fdc0eb8ebe9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007fdc0edb7da0 R08: 00000000000038f0 R09: 000000109089fdcf
R10: 00000000003fc4ec R11: 0000000000000246 R12: 0000000000016154
R13: 00007fdc0edb6180 R14: ffffffffffffffff R15: 00007ffc9089fbf0
 </TASK>

Allocated by task 1:
 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
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 dvb_register_device+0x1e4/0x2370 drivers/media/dvb-core/dvbdev.c:475
 dvb_register_frontend+0x5a6/0x880 drivers/media/dvb-core/dvb_frontend.c:3051
 vidtv_bridge_dvb_init drivers/media/test-drivers/vidtv/vidtv_bridge.c:436 [inline]
 vidtv_bridge_probe+0x459/0xa90 drivers/media/test-drivers/vidtv/vidtv_bridge.c:508
 platform_probe+0x103/0x1d0 drivers/base/platform.c:1405
 call_driver_probe drivers/base/dd.c:581 [inline]
 really_probe+0x241/0xa90 drivers/base/dd.c:659
 __driver_probe_device+0x1de/0x440 drivers/base/dd.c:801
 driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:831
 __driver_attach+0x283/0x580 drivers/base/dd.c:1217
 bus_for_each_dev+0x13e/0x1d0 drivers/base/bus.c:370
 bus_add_driver+0x2e9/0x690 drivers/base/bus.c:678
 driver_register+0x15c/0x4b0 drivers/base/driver.c:249
 vidtv_bridge_init+0x45/0x80 drivers/media/test-drivers/vidtv/vidtv_bridge.c:598
 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+0x5d4/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Freed by task 6068:
 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
 dvb_free_device drivers/media/dvb-core/dvbdev.c:619 [inline]
 kref_put include/linux/kref.h:65 [inline]
 dvb_device_put.part.0+0x60/0x90 drivers/media/dvb-core/dvbdev.c:632
 dvb_device_put drivers/media/dvb-core/dvbdev.c:171 [inline]
 dvb_generic_release+0xe2/0x160 drivers/media/dvb-core/dvbdev.c:169
 dvb_frontend_release+0x13d/0x5b0 drivers/media/dvb-core/dvb_frontend.c:2914
 __fput+0x3ff/0xb70 fs/file_table.c:468
 task_work_run+0x14d/0x240 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop+0xeb/0x110 kernel/entry/common.c:43
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 do_syscall_64+0x3f6/0x490 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888029c17600
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 60 bytes inside of
 freed 256-byte region [ffff888029c17600, ffff888029c17700)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x29c16
head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88801b841b40 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88801b841b40 dead000000000122 0000000000000000
head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000001 ffffea0000a70581 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 18229959533, 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
 usb_register_driver+0x216/0x4d0 drivers/usb/core/driver.c:1078
 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+0x5d4/0x6f0 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:
 ffff888029c17500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888029c17580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888029c17600: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                        ^
 ffff888029c17680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888029c17700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/08/23 09:59 upstream 6debb6904172 bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: slab-use-after-free Read in dvb_frontend_release
2025/08/23 09:51 upstream 6debb6904172 bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: slab-use-after-free Read in dvb_frontend_release
2025/08/23 09:50 upstream 6debb6904172 bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto KASAN: slab-use-after-free Read in dvb_frontend_release
* Struck through repros no longer work on HEAD.