================================================================== BUG: KFENCE: use-after-free read in dvb_device_open+0xee/0x3b0 drivers/media/dvb-core/dvbdev.c:99 Use-after-free read at 0xffff88823bf42f18 (in kfence-#160): dvb_device_open+0xee/0x3b0 drivers/media/dvb-core/dvbdev.c:99 chrdev_open+0x231/0x6a0 fs/char_dev.c:414 do_dentry_open+0x741/0x1c10 fs/open.c:956 vfs_open+0x82/0x3f0 fs/open.c:1086 do_open fs/namei.c:3880 [inline] path_openat+0x1e5e/0x2d40 fs/namei.c:4039 do_filp_open+0x20b/0x470 fs/namei.c:4066 do_sys_openat2+0x11b/0x1d0 fs/open.c:1429 do_sys_open fs/open.c:1444 [inline] __do_sys_openat fs/open.c:1460 [inline] __se_sys_openat fs/open.c:1455 [inline] __x64_sys_openat+0x174/0x210 fs/open.c:1455 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x230 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f kfence-#160: 0xffff88823bf42000-0xffff88823bf420ef, size=240, cache=skbuff_head_cache allocated by task 22903 on cpu 1 at 1490.466553s (1.518062s ago): __alloc_skb+0x2b2/0x380 net/core/skbuff.c:658 alloc_skb include/linux/skbuff.h:1340 [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+0x2b1/0xcf0 drivers/net/netdevsim/dev.c:851 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 freed by task 22903 on cpu 1 at 1490.466611s (1.561413s ago): kfree_skbmem+0x1a4/0x1f0 net/core/skbuff.c:1120 __kfree_skb net/core/skbuff.c:1177 [inline] consume_skb net/core/skbuff.c:1408 [inline] consume_skb+0xcc/0x100 net/core/skbuff.c:1402 nsim_dev_trap_report drivers/net/netdevsim/dev.c:821 [inline] nsim_dev_trap_report_work+0x8bd/0xcf0 drivers/net/netdevsim/dev.c:851 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 CPU: 1 UID: 0 PID: 25120 Comm: syz.0.3392 Tainted: G U 6.15.0-rc4-syzkaller-00256-g95d3481af6dc #0 PREEMPT(full) Tainted: [U]=USER Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025 RIP: 0010:dvb_device_open+0xee/0x3b0 drivers/media/dvb-core/dvbdev.c:99 Code: 0f 84 3f 02 00 00 e8 b1 2b f4 f9 48 8d 7d 18 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 77 02 00 00 <4c> 8b 6d 18 4d 85 ed 0f 84 0e 02 00 00 e8 80 2b f4 f9 4c 89 ea 48 RSP: 0018:ffffc900046a7920 EFLAGS: 00010246 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffc90010f3e000 RDX: 1ffff110477e85e3 RSI: ffffffff87c6811f RDI: ffff88823bf42f18 RBP: ffff88823bf42f00 R08: 0000000000000001 R09: fffffbfff1f41d3d R10: ffffffff8fa0e9ef R11: 0000000000000000 R12: ffff88805b435180 R13: ffffffff87c68050 R14: ffff888029e8d668 R15: ffff88805b4351c8 FS: 00007f19491e96c0(0000) GS:ffff888124aec000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff88823bf42f18 CR3: 0000000058cc8000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: chrdev_open+0x231/0x6a0 fs/char_dev.c:414 do_dentry_open+0x741/0x1c10 fs/open.c:956 vfs_open+0x82/0x3f0 fs/open.c:1086 do_open fs/namei.c:3880 [inline] path_openat+0x1e5e/0x2d40 fs/namei.c:4039 do_filp_open+0x20b/0x470 fs/namei.c:4066 do_sys_openat2+0x11b/0x1d0 fs/open.c:1429 do_sys_open fs/open.c:1444 [inline] __do_sys_openat fs/open.c:1460 [inline] __se_sys_openat fs/open.c:1455 [inline] __x64_sys_openat+0x174/0x210 fs/open.c:1455 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x230 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f194838e969 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:00007f19491e9038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f19485b6080 RCX: 00007f194838e969 RDX: 0000000000100000 RSI: 0000200000000200 RDI: ffffffffffffff9c RBP: 00007f1948410ab1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f19485b6080 R15: 00007ffc27a21ae8 ================================================================== ---------------- Code disassembly (best guess): 0: 0f 84 3f 02 00 00 je 0x245 6: e8 b1 2b f4 f9 call 0xf9f42bbc b: 48 8d 7d 18 lea 0x18(%rbp),%rdi f: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 16: fc ff df 19: 48 89 fa mov %rdi,%rdx 1c: 48 c1 ea 03 shr $0x3,%rdx 20: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) 24: 0f 85 77 02 00 00 jne 0x2a1 * 2a: 4c 8b 6d 18 mov 0x18(%rbp),%r13 <-- trapping instruction 2e: 4d 85 ed test %r13,%r13 31: 0f 84 0e 02 00 00 je 0x245 37: e8 80 2b f4 f9 call 0xf9f42bbc 3c: 4c 89 ea mov %r13,%rdx 3f: 48 rex.W