================================================================== BUG: KFENCE: use-after-free read in dvb_frontend_release+0x150/0x4d0 drivers/media/dvb-core/dvb_frontend.c:2916 Use-after-free read at 0xffff88805b30603c (in kfence-#130): dvb_frontend_release+0x150/0x4d0 drivers/media/dvb-core/dvb_frontend.c:2916 __fput+0x44f/0xa60 fs/file_table.c:510 task_work_run+0x1d9/0x270 kernel/task_work.c:233 get_signal+0x11eb/0x1330 kernel/signal.c:2809 arch_do_signal_or_restart+0xbc/0x840 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline] exit_to_user_mode_loop+0xa9/0x680 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline] do_syscall_64+0x353/0x580 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f kfence-#130: 0xffff88805b306000-0xffff88805b3060d7, size=216, cache=kmalloc-256 allocated by task 1 on cpu 0 at 26.019897s (76.881208s ago): kmalloc_noprof include/linux/slab.h:950 [inline] kzalloc_noprof include/linux/slab.h:1188 [inline] dvb_register_device+0x2fd/0x21e0 drivers/media/dvb-core/dvbdev.c:472 dvb_register_frontend+0x61b/0x920 drivers/media/dvb-core/dvb_frontend.c:3051 vidtv_bridge_dvb_init drivers/media/test-drivers/vidtv/vidtv_bridge.c:438 [inline] vidtv_bridge_probe+0x9aa/0xf80 drivers/media/test-drivers/vidtv/vidtv_bridge.c:510 platform_probe+0xf9/0x190 drivers/base/platform.c:1432 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x267/0xaf0 drivers/base/dd.c:709 __driver_probe_device+0x1ef/0x380 drivers/base/dd.c:871 driver_probe_device+0x4f/0x240 drivers/base/dd.c:901 __driver_attach+0x34c/0x640 drivers/base/dd.c:1295 bus_for_each_dev+0x23b/0x2c0 drivers/base/bus.c:383 bus_add_driver+0x345/0x670 drivers/base/bus.c:756 driver_register+0x23a/0x320 drivers/base/driver.c:249 vidtv_bridge_init+0x28/0x50 drivers/media/test-drivers/vidtv/vidtv_bridge.c:600 do_one_initcall+0x250/0x870 init/main.c:1392 do_initcall_level+0x104/0x190 init/main.c:1454 do_initcalls+0x59/0xa0 init/main.c:1470 kernel_init_freeable+0x2a6/0x3e0 init/main.c:1703 kernel_init+0x1d/0x1d0 init/main.c:1593 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 freed by task 5341 on cpu 0 at 102.867644s (0.075086s ago): dvb_free_device drivers/media/dvb-core/dvbdev.c:616 [inline] kref_put include/linux/kref.h:65 [inline] dvb_device_put drivers/media/dvb-core/dvbdev.c:629 [inline] dvb_generic_release+0x11d/0x1b0 drivers/media/dvb-core/dvbdev.c:169 dvb_frontend_release+0x132/0x4d0 drivers/media/dvb-core/dvb_frontend.c:2914 __fput+0x44f/0xa60 fs/file_table.c:510 task_work_run+0x1d9/0x270 kernel/task_work.c:233 get_signal+0x11eb/0x1330 kernel/signal.c:2809 arch_do_signal_or_restart+0xbc/0x840 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline] exit_to_user_mode_loop+0xa9/0x680 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline] do_syscall_64+0x353/0x580 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f CPU: 0 UID: 0 PID: 5341 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 RIP: 0010:dvb_frontend_release+0x150/0x4d0 drivers/media/dvb-core/dvb_frontend.c:2916 Code: f9 4c 89 e7 4c 89 fe e8 ee b8 fd ff 89 c5 48 8b 04 24 4c 8d 78 3c 4c 89 f8 48 c1 e8 03 42 0f b6 04 30 84 c0 0f 85 a1 02 00 00 <45> 8b 3f bf ff ff ff ff 44 89 fe e8 10 36 de f9 41 83 ff ff 74 0a RSP: 0018:ffffc9000e09fae8 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff888033374000 RCX: ffffffff8232d5a9 RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffffffff9a4aea50 RBP: 0000000000000000 R08: ffffffff9a4aea57 R09: 1ffffffff3495d4a R10: dffffc0000000000 R11: fffffbfff3495d4b R12: ffff88803918f740 R13: ffff888030436000 R14: dffffc0000000000 R15: ffff88805b30603c FS: 0000555557a03540(0000) GS:ffff88808c895000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff88805b30603c CR3: 0000000044875000 CR4: 0000000000352ef0 Call Trace: __fput+0x44f/0xa60 fs/file_table.c:510 task_work_run+0x1d9/0x270 kernel/task_work.c:233 get_signal+0x11eb/0x1330 kernel/signal.c:2809 arch_do_signal_or_restart+0xbc/0x840 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline] exit_to_user_mode_loop+0xa9/0x680 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline] do_syscall_64+0x353/0x580 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb48219ce59 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffd3b9cba08 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007fb482417da0 RCX: 00007fb48219ce59 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 00007fb482417da0 R08: 0000000000000006 R09: 0000000000000000 R10: 0000000000dffd24 R11: 0000000000000246 R12: 00000000000193f7 R13: 00007fb48241609c R14: 00007fb482416098 R15: 00007fb482416090 ================================================================== ---------------- Code disassembly (best guess): 0: f9 stc 1: 4c 89 e7 mov %r12,%rdi 4: 4c 89 fe mov %r15,%rsi 7: e8 ee b8 fd ff call 0xfffdb8fa c: 89 c5 mov %eax,%ebp e: 48 8b 04 24 mov (%rsp),%rax 12: 4c 8d 78 3c lea 0x3c(%rax),%r15 16: 4c 89 f8 mov %r15,%rax 19: 48 c1 e8 03 shr $0x3,%rax 1d: 42 0f b6 04 30 movzbl (%rax,%r14,1),%eax 22: 84 c0 test %al,%al 24: 0f 85 a1 02 00 00 jne 0x2cb * 2a: 45 8b 3f mov (%r15),%r15d <-- trapping instruction 2d: bf ff ff ff ff mov $0xffffffff,%edi 32: 44 89 fe mov %r15d,%esi 35: e8 10 36 de f9 call 0xf9de364a 3a: 41 83 ff ff cmp $0xffffffff,%r15d 3e: 74 0a je 0x4a