================================================================== BUG: KFENCE: use-after-free read in dvb_device_open+0xc4/0x350 drivers/media/dvb-core/dvbdev.c:99 Use-after-free read at 0xffff88823bf0af18 (in kfence-#132): dvb_device_open+0xc4/0x350 drivers/media/dvb-core/dvbdev.c:99 chrdev_open+0x4cd/0x5e0 fs/char_dev.c:411 do_dentry_open+0x785/0x14e0 fs/open.c:949 vfs_open+0x3b/0x340 fs/open.c:1081 do_open fs/namei.c:4671 [inline] path_openat+0x2e08/0x3860 fs/namei.c:4830 do_file_open+0x23e/0x4a0 fs/namei.c:4859 do_sys_openat2+0x113/0x200 fs/open.c:1366 do_sys_open fs/open.c:1372 [inline] __do_sys_openat fs/open.c:1388 [inline] __se_sys_openat fs/open.c:1383 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1383 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f kfence-#132: 0xffff88823bf0af00-0xffff88823bf0afd7, size=216, cache=kmalloc-256 allocated by task 1 on cpu 0 at 17.388422s (106.055591s ago): kmalloc_noprof include/linux/slab.h:962 [inline] kzalloc_noprof include/linux/slab.h:1204 [inline] dvb_register_device+0x2fd/0x2210 drivers/media/dvb-core/dvbdev.c:475 dvb_register_frontend+0x649/0x950 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+0x9aa/0xf80 drivers/media/test-drivers/vidtv/vidtv_bridge.c:508 platform_probe+0xf9/0x190 drivers/base/platform.c:1446 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x267/0xaf0 drivers/base/dd.c:661 __driver_probe_device+0x18c/0x320 drivers/base/dd.c:803 driver_probe_device+0x4f/0x240 drivers/base/dd.c:833 __driver_attach+0x3e7/0x710 drivers/base/dd.c:1227 bus_for_each_dev+0x23b/0x2c0 drivers/base/bus.c:383 bus_add_driver+0x345/0x670 drivers/base/bus.c:715 driver_register+0x23a/0x320 drivers/base/driver.c:249 vidtv_bridge_init+0x28/0x50 drivers/media/test-drivers/vidtv/vidtv_bridge.c:598 do_one_initcall+0x250/0x8d0 init/main.c:1382 do_initcall_level+0x104/0x190 init/main.c:1444 do_initcalls+0x59/0xa0 init/main.c:1460 kernel_init_freeable+0x2a6/0x3e0 init/main.c:1692 kernel_init+0x1d/0x1d0 init/main.c:1582 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 freed by task 6181 on cpu 1 at 123.351374s (0.195053s ago): 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+0x2cd/0x350 drivers/media/dvb-core/dvbdev.c:113 chrdev_open+0x4cd/0x5e0 fs/char_dev.c:411 do_dentry_open+0x785/0x14e0 fs/open.c:949 vfs_open+0x3b/0x340 fs/open.c:1081 do_open fs/namei.c:4671 [inline] path_openat+0x2e08/0x3860 fs/namei.c:4830 do_file_open+0x23e/0x4a0 fs/namei.c:4859 do_sys_openat2+0x113/0x200 fs/open.c:1366 do_sys_open fs/open.c:1372 [inline] __do_sys_openat fs/open.c:1388 [inline] __se_sys_openat fs/open.c:1383 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1383 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f CPU: 0 UID: 0 PID: 6182 Comm: syz.2.51 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 RIP: 0010:dvb_device_open+0xc4/0x350 drivers/media/dvb-core/dvbdev.c:99 Code: e8 f1 04 46 fa 4d 8b 3f 4d 85 ff 0f 84 64 01 00 00 4d 8d 67 18 4c 89 e0 48 c1 e8 03 80 3c 18 00 74 08 4c 89 e7 e8 cc 04 46 fa <4d> 8b 2c 24 4d 85 ed 0f 84 45 01 00 00 4c 89 e8 48 c1 e8 03 80 3c RSP: 0018:ffffc90003ce7770 EFLAGS: 00010246 RAX: 1ffff110477e15e3 RBX: dffffc0000000000 RCX: 0000000000000000 RDX: 0000000000000001 RSI: 0000000000000008 RDI: 00000000ffffffff RBP: ffff88807e881dc0 R08: ffffffff8f8db04f R09: 1ffffffff1f1b609 R10: dffffc0000000000 R11: fffffbfff1f1b60a R12: ffff88823bf0af18 R13: dffffc0000000000 R14: ffff88802c65ef78 R15: ffff88823bf0af00 FS: 00007fc3d01fe6c0(0000) GS:ffff888125010000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff88823bf0af18 CR3: 000000007bff4000 CR4: 00000000003526f0 Call Trace: chrdev_open+0x4cd/0x5e0 fs/char_dev.c:411 do_dentry_open+0x785/0x14e0 fs/open.c:949 vfs_open+0x3b/0x340 fs/open.c:1081 do_open fs/namei.c:4671 [inline] path_openat+0x2e08/0x3860 fs/namei.c:4830 do_file_open+0x23e/0x4a0 fs/namei.c:4859 do_sys_openat2+0x113/0x200 fs/open.c:1366 do_sys_open fs/open.c:1372 [inline] __do_sys_openat fs/open.c:1388 [inline] __se_sys_openat fs/open.c:1383 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1383 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fc3d0b5c84e 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:00007fc3d01fdb28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fc3d01fe6c0 RCX: 00007fc3d0b5c84e RDX: 0000000000040002 RSI: 00007fc3d01fdc00 RDI: ffffffffffffff9c RBP: 00007fc3d01fdc00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd R13: 00007fc3d0e16128 R14: 00007fc3d0e16090 R15: 00007ffc64b1c038 ================================================================== ---------------- Code disassembly (best guess): 0: e8 f1 04 46 fa call 0xfa4604f6 5: 4d 8b 3f mov (%r15),%r15 8: 4d 85 ff test %r15,%r15 b: 0f 84 64 01 00 00 je 0x175 11: 4d 8d 67 18 lea 0x18(%r15),%r12 15: 4c 89 e0 mov %r12,%rax 18: 48 c1 e8 03 shr $0x3,%rax 1c: 80 3c 18 00 cmpb $0x0,(%rax,%rbx,1) 20: 74 08 je 0x2a 22: 4c 89 e7 mov %r12,%rdi 25: e8 cc 04 46 fa call 0xfa4604f6 * 2a: 4d 8b 2c 24 mov (%r12),%r13 <-- trapping instruction 2e: 4d 85 ed test %r13,%r13 31: 0f 84 45 01 00 00 je 0x17c 37: 4c 89 e8 mov %r13,%rax 3a: 48 c1 e8 03 shr $0x3,%rax 3e: 80 .byte 0x80 3f: 3c .byte 0x3c