================================================================== BUG: KFENCE: use-after-free read in dvb_device_open+0xc6/0x370 drivers/media/dvb-core/dvbdev.c:99 Use-after-free read at 0xffff88823bc70f18 (in kfence-#55): dvb_device_open+0xc6/0x370 drivers/media/dvb-core/dvbdev.c:99 chrdev_open+0x5c5/0x6a0 fs/char_dev.c:414 do_dentry_open+0x7e9/0x10d0 fs/open.c:882 do_open fs/namei.c:3634 [inline] path_openat+0x2635/0x2ee0 fs/namei.c:3791 do_filp_open+0x1f1/0x430 fs/namei.c:3818 do_sys_openat2+0x150/0x4b0 fs/open.c:1320 do_sys_open fs/open.c:1336 [inline] __do_sys_openat fs/open.c:1352 [inline] __se_sys_openat fs/open.c:1347 [inline] __x64_sys_openat+0x135/0x160 fs/open.c:1347 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 kfence-#55: 0xffff88823bc70f00-0xffff88823bc70fd7, size=216, cache=kmalloc-256 allocated by task 1 on cpu 1 at 13.064378s: kfence_alloc include/linux/kfence.h:128 [inline] slab_alloc_node mm/slub.c:3283 [inline] __kmem_cache_alloc_node+0x1fa/0x260 mm/slub.c:3398 kmalloc_trace+0x26/0xe0 mm/slab_common.c:1026 kmalloc include/linux/slab.h:563 [inline] kzalloc include/linux/slab.h:699 [inline] dvb_register_device+0x311/0x2150 drivers/media/dvb-core/dvbdev.c:478 dvb_register_frontend+0x645/0x920 drivers/media/dvb-core/dvb_frontend.c:3035 vidtv_bridge_dvb_init drivers/media/test-drivers/vidtv/vidtv_bridge.c:436 [inline] vidtv_bridge_probe+0x9a1/0xf70 drivers/media/test-drivers/vidtv/vidtv_bridge.c:508 platform_probe+0x137/0x1c0 drivers/base/platform.c:1400 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x2aa/0xc70 drivers/base/dd.c:639 __driver_probe_device+0x18c/0x330 drivers/base/dd.c:785 driver_probe_device+0x4f/0x420 drivers/base/dd.c:815 __driver_attach+0x44a/0x6e0 drivers/base/dd.c:1201 bus_for_each_dev+0x182/0x1f0 drivers/base/bus.c:303 bus_add_driver+0x30a/0x5a0 drivers/base/bus.c:620 driver_register+0x32d/0x430 drivers/base/driver.c:246 vidtv_bridge_init+0x39/0x67 drivers/media/test-drivers/vidtv/vidtv_bridge.c:600 do_one_initcall+0x26a/0x840 init/main.c:1310 do_initcall_level+0x137/0x1e4 init/main.c:1383 do_initcalls+0x4b/0x8a init/main.c:1399 kernel_init_freeable+0x415/0x5be init/main.c:1638 kernel_init+0x19/0x1b0 init/main.c:1526 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 freed by task 9539 on cpu 1 at 526.968511s: dvb_free_device drivers/media/dvb-core/dvbdev.c:625 [inline] kref_put include/linux/kref.h:65 [inline] dvb_device_put drivers/media/dvb-core/dvbdev.c:640 [inline] dvb_device_open+0x2e7/0x370 drivers/media/dvb-core/dvbdev.c:113 chrdev_open+0x5c5/0x6a0 fs/char_dev.c:414 do_dentry_open+0x7e9/0x10d0 fs/open.c:882 do_open fs/namei.c:3634 [inline] path_openat+0x2635/0x2ee0 fs/namei.c:3791 do_filp_open+0x1f1/0x430 fs/namei.c:3818 do_sys_openat2+0x150/0x4b0 fs/open.c:1320 do_sys_open fs/open.c:1336 [inline] __do_sys_openat fs/open.c:1352 [inline] __se_sys_openat fs/open.c:1347 [inline] __x64_sys_openat+0x135/0x160 fs/open.c:1347 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 CPU: 1 PID: 9623 Comm: syz.2.1340 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 RIP: 0010:dvb_device_open+0xc6/0x370 drivers/media/dvb-core/dvbdev.c:99 Code: 8b 3f 4d 85 ff 0f 84 80 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 2a 21 0e fb <4d> 8b 2c 24 4d 85 ed 0f 84 5b 01 00 00 4c 89 e8 48 c1 e8 03 80 3c RSP: 0018:ffffc900052c77b0 EFLAGS: 00010246 RAX: 1ffffffff2df821b RBX: dffffc0000000000 RCX: 0000000000000000 RDX: 0000000000000001 RSI: 0000000000000008 RDI: 00000000ffffffff RBP: 1ffff1104778e1e3 R08: ffffffff8d8ac92f R09: 1ffffffff1b15925 R10: dffffc0000000000 R11: fffffbfff1b15926 R12: ffff88823bc70f18 R13: 1ffff92000a58f04 R14: ffff888029202720 R15: ffff88823bc70f00 FS: 00007fed67df66c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff88823bc70f18 CR3: 0000000025054000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: chrdev_open+0x5c5/0x6a0 fs/char_dev.c:414 do_dentry_open+0x7e9/0x10d0 fs/open.c:882 do_open fs/namei.c:3634 [inline] path_openat+0x2635/0x2ee0 fs/namei.c:3791 do_filp_open+0x1f1/0x430 fs/namei.c:3818 do_sys_openat2+0x150/0x4b0 fs/open.c:1320 do_sys_open fs/open.c:1336 [inline] __do_sys_openat fs/open.c:1352 [inline] __se_sys_openat fs/open.c:1347 [inline] __x64_sys_openat+0x135/0x160 fs/open.c:1347 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fed69b5c84e 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:00007fed67df5b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fed67df66c0 RCX: 00007fed69b5c84e RDX: 0000000000000002 RSI: 00007fed67df5c00 RDI: ffffffffffffff9c RBP: 00007fed67df5c00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd R13: 00007fed69e16038 R14: 00007fed69e15fa0 R15: 00007ffe9d925078 ================================================================== ---------------- Code disassembly (best guess): 0: 8b 3f mov (%rdi),%edi 2: 4d 85 ff test %r15,%r15 5: 0f 84 80 01 00 00 je 0x18b 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 2a 21 0e fb call 0xfb0e2154 * 2a: 4d 8b 2c 24 mov (%r12),%r13 <-- trapping instruction 2e: 4d 85 ed test %r13,%r13 31: 0f 84 5b 01 00 00 je 0x192 37: 4c 89 e8 mov %r13,%rax 3a: 48 c1 e8 03 shr $0x3,%rax 3e: 80 .byte 0x80 3f: 3c .byte 0x3c