================================================================== BUG: KFENCE: use-after-free read in dvb_device_open+0xc9/0x360 drivers/media/dvb-core/dvbdev.c:99 Use-after-free read at 0xffff88823bdccf18 (in kfence-#229): dvb_device_open+0xc9/0x360 drivers/media/dvb-core/dvbdev.c:99 chrdev_open+0x58c/0x600 fs/char_dev.c:414 do_dentry_open+0x880/0x14b0 fs/open.c:929 do_open fs/namei.c:3683 [inline] path_openat+0x284f/0x3270 fs/namei.c:3844 do_filp_open+0x1f2/0x430 fs/namei.c:3871 do_sys_openat2+0x134/0x1d0 fs/open.c:1422 do_sys_open fs/open.c:1437 [inline] __do_sys_openat fs/open.c:1453 [inline] __se_sys_openat fs/open.c:1448 [inline] __x64_sys_openat+0x139/0x160 fs/open.c:1448 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 kfence-#229: 0xffff88823bdcc000-0xffff88823bdcc0ef, size=240, cache=skbuff_head_cache allocated by task 6549 on cpu 0 at 321.553501s: __alloc_skb+0x103/0x2c0 net/core/skbuff.c:643 alloc_skb include/linux/skbuff.h:1316 [inline] nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:748 [inline] nsim_dev_trap_report drivers/net/netdevsim/dev.c:805 [inline] nsim_dev_trap_report_work+0x253/0xa90 drivers/net/netdevsim/dev.c:851 process_one_work kernel/workqueue.c:2657 [inline] process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2734 worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2815 kthread+0x2fa/0x390 kernel/kthread.c:388 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 6549 on cpu 0 at 321.553559s: nsim_dev_trap_report drivers/net/netdevsim/dev.c:821 [inline] nsim_dev_trap_report_work+0x723/0xa90 drivers/net/netdevsim/dev.c:851 process_one_work kernel/workqueue.c:2657 [inline] process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2734 worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2815 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 CPU: 1 PID: 7756 Comm: syz.4.426 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:dvb_device_open+0xc9/0x360 drivers/media/dvb-core/dvbdev.c:99 Code: 4d 8b 3f 4d 85 ff 0f 84 2f 01 00 00 4c 89 24 24 4d 8d 67 18 4c 89 e5 48 c1 ed 03 80 7c 1d 00 00 74 08 4c 89 e7 e8 b7 12 d3 fa <4d> 8b 2c 24 4d 85 ed 0f 84 0b 01 00 00 4c 89 e8 48 c1 e8 03 80 3c RSP: 0018:ffffc9000c4877f0 EFLAGS: 00010246 RAX: 1ffffffff2ecc68f RBX: dffffc0000000000 RCX: 0000000000000000 RDX: 0000000000000001 RSI: 0000000000000008 RDI: 00000000ffffffff RBP: 1ffff110477b99e3 R08: ffffffff8df11f8f R09: 1ffffffff1be23f1 R10: dffffc0000000000 R11: fffffbfff1be23f2 R12: ffff88823bdccf18 R13: dffffc0000000000 R14: ffff88802694a9f8 R15: ffff88823bdccf00 FS: 00007ff280dde6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff88823bdccf18 CR3: 000000005ef54000 CR4: 00000000003506e0 Call Trace: chrdev_open+0x58c/0x600 fs/char_dev.c:414 do_dentry_open+0x880/0x14b0 fs/open.c:929 do_open fs/namei.c:3683 [inline] path_openat+0x284f/0x3270 fs/namei.c:3844 do_filp_open+0x1f2/0x430 fs/namei.c:3871 do_sys_openat2+0x134/0x1d0 fs/open.c:1422 do_sys_open fs/open.c:1437 [inline] __do_sys_openat fs/open.c:1453 [inline] __se_sys_openat fs/open.c:1448 [inline] __x64_sys_openat+0x139/0x160 fs/open.c:1448 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7ff27ff5e98e 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:00007ff280dddb28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007ff280dde6c0 RCX: 00007ff27ff5e98e RDX: 0000000000040002 RSI: 00007ff280dddc00 RDI: ffffffffffffff9c RBP: 00007ff280dddc00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd R13: 00007ff280226308 R14: 00007ff280226270 R15: 00007ffe558dc968 ================================================================== ---------------- Code disassembly (best guess): 0: 4d 8b 3f mov (%r15),%r15 3: 4d 85 ff test %r15,%r15 6: 0f 84 2f 01 00 00 je 0x13b c: 4c 89 24 24 mov %r12,(%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 b7 12 d3 fa call 0xfad312e1 * 2a: 4d 8b 2c 24 mov (%r12),%r13 <-- trapping instruction 2e: 4d 85 ed test %r13,%r13 31: 0f 84 0b 01 00 00 je 0x142 37: 4c 89 e8 mov %r13,%rax 3a: 48 c1 e8 03 shr $0x3,%rax 3e: 80 .byte 0x80 3f: 3c .byte 0x3c