================================================================== BUG: KFENCE: use-after-free read in dvb_device_open+0xca/0x370 drivers/media/dvb-core/dvbdev.c:99 Use-after-free read at 0xffff88823bd26f18 (in kfence-#146): dvb_device_open+0xca/0x370 drivers/media/dvb-core/dvbdev.c:99 chrdev_open+0x5cc/0x6a0 fs/char_dev.c:414 do_dentry_open+0x8c6/0x1500 fs/open.c:929 do_open fs/namei.c:3640 [inline] path_openat+0x27f1/0x3230 fs/namei.c:3797 do_filp_open+0x1f5/0x430 fs/namei.c:3824 do_sys_openat2+0x134/0x1d0 fs/open.c:1421 do_sys_open fs/open.c:1436 [inline] __do_sys_openat fs/open.c:1452 [inline] __se_sys_openat fs/open.c:1447 [inline] __x64_sys_openat+0x139/0x160 fs/open.c:1447 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 kfence-#146: 0xffff88823bd26f00-0xffff88823bd26fd7, size=216, cache=kmalloc-256 allocated by task 1 on cpu 0 at 12.886904s: kfence_alloc include/linux/kfence.h:129 [inline] slab_alloc_node mm/slub.c:3481 [inline] __kmem_cache_alloc_node+0x1f7/0x250 mm/slub.c:3534 kmalloc_trace+0x2a/0xe0 mm/slab_common.c:1098 kmalloc include/linux/slab.h:600 [inline] kzalloc include/linux/slab.h:721 [inline] dvb_register_device+0x2fd/0x2210 drivers/media/dvb-core/dvbdev.c:475 dvb_register_frontend+0x649/0x930 drivers/media/dvb-core/dvb_frontend.c:3056 vidtv_bridge_dvb_init drivers/media/test-drivers/vidtv/vidtv_bridge.c:436 [inline] vidtv_bridge_probe+0x9ab/0xf80 drivers/media/test-drivers/vidtv/vidtv_bridge.c:508 platform_probe+0x13b/0x1c0 drivers/base/platform.c:1404 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x25b/0xb20 drivers/base/dd.c:658 __driver_probe_device+0x18c/0x330 drivers/base/dd.c:800 driver_probe_device+0x4f/0x420 drivers/base/dd.c:830 __driver_attach+0x44e/0x6e0 drivers/base/dd.c:1216 bus_for_each_dev+0x235/0x2b0 drivers/base/bus.c:370 bus_add_driver+0x340/0x630 drivers/base/bus.c:675 driver_register+0x23a/0x310 drivers/base/driver.c:246 vidtv_bridge_init+0x3d/0x70 drivers/media/test-drivers/vidtv/vidtv_bridge.c:598 do_one_initcall+0x242/0x790 init/main.c:1250 do_initcall_level+0x137/0x1f0 init/main.c:1312 do_initcalls+0x69/0xd0 init/main.c:1328 kernel_init_freeable+0x3ed/0x580 init/main.c:1565 kernel_init+0x1d/0x1c0 init/main.c:1455 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 freed by task 8942 on cpu 1 at 333.350936s: dvb_free_device drivers/media/dvb-core/dvbdev.c:619 [inline] kref_put include/linux/kref.h:65 [inline] dvb_device_put drivers/media/dvb-core/dvbdev.c:632 [inline] dvb_device_open+0x2ee/0x370 drivers/media/dvb-core/dvbdev.c:113 chrdev_open+0x5cc/0x6a0 fs/char_dev.c:414 do_dentry_open+0x8c6/0x1500 fs/open.c:929 do_open fs/namei.c:3640 [inline] path_openat+0x27f1/0x3230 fs/namei.c:3797 do_filp_open+0x1f5/0x430 fs/namei.c:3824 do_sys_openat2+0x134/0x1d0 fs/open.c:1421 do_sys_open fs/open.c:1436 [inline] __do_sys_openat fs/open.c:1452 [inline] __se_sys_openat fs/open.c:1447 [inline] __x64_sys_openat+0x139/0x160 fs/open.c:1447 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 CPU: 1 PID: 8979 Comm: syz.1.751 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 RIP: 0010:dvb_device_open+0xca/0x370 drivers/media/dvb-core/dvbdev.c:99 Code: 8b 3f 4d 85 ff 0f 84 83 01 00 00 4c 89 64 24 08 4d 8d 67 18 4c 89 e5 48 c1 ed 03 80 7c 1d 00 00 74 08 4c 89 e7 e8 c6 80 dd fa <4d> 8b 2c 24 4d 85 ed 0f 84 5e 01 00 00 4c 89 e8 48 c1 e8 03 80 3c RSP: 0018:ffffc9000d0777f0 EFLAGS: 00010246 RAX: 1ffffffff2ec59db RBX: dffffc0000000000 RCX: 0000000000000000 RDX: 0000000000000001 RSI: 0000000000000008 RDI: 00000000ffffffff RBP: 1ffff110477a4de3 R08: ffffffff8defe9cf R09: 1ffffffff1bdfd39 R10: dffffc0000000000 R11: fffffbfff1bdfd3a R12: ffff88823bd26f18 R13: 1ffff92001a0ef0c R14: ffff88802662d900 R15: ffff88823bd26f00 FS: 00007f33013f66c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff88823bd26f18 CR3: 000000002b4c9000 CR4: 00000000003506e0 Call Trace: chrdev_open+0x5cc/0x6a0 fs/char_dev.c:414 do_dentry_open+0x8c6/0x1500 fs/open.c:929 do_open fs/namei.c:3640 [inline] path_openat+0x27f1/0x3230 fs/namei.c:3797 do_filp_open+0x1f5/0x430 fs/namei.c:3824 do_sys_openat2+0x134/0x1d0 fs/open.c:1421 do_sys_open fs/open.c:1436 [inline] __do_sys_openat fs/open.c:1452 [inline] __se_sys_openat fs/open.c:1447 [inline] __x64_sys_openat+0x139/0x160 fs/open.c:1447 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f330315cfce 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:00007f33013f5b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f33013f66c0 RCX: 00007f330315cfce RDX: 0000000000000e82 RSI: 00007f33013f5c00 RDI: ffffffffffffff9c RBP: 00007f33013f5c00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd R13: 00007f3303416128 R14: 00007f3303416090 R15: 00007fff0713f2f8 ================================================================== ---------------- Code disassembly (best guess): 0: 8b 3f mov (%rdi),%edi 2: 4d 85 ff test %r15,%r15 5: 0f 84 83 01 00 00 je 0x18e b: 4c 89 64 24 08 mov %r12,0x8(%rsp) 10: 4d 8d 67 18 lea 0x18(%r15),%r12 14: 4c 89 e5 mov %r12,%rbp 17: 48 c1 ed 03 shr $0x3,%rbp 1b: 80 7c 1d 00 00 cmpb $0x0,0x0(%rbp,%rbx,1) 20: 74 08 je 0x2a 22: 4c 89 e7 mov %r12,%rdi 25: e8 c6 80 dd fa call 0xfadd80f0 * 2a: 4d 8b 2c 24 mov (%r12),%r13 <-- trapping instruction 2e: 4d 85 ed test %r13,%r13 31: 0f 84 5e 01 00 00 je 0x195 37: 4c 89 e8 mov %r13,%rax 3a: 48 c1 e8 03 shr $0x3,%rax 3e: 80 .byte 0x80 3f: 3c .byte 0x3c