================================================================== BUG: KFENCE: use-after-free read in dvb_frontend_release+0x150/0x4d0 drivers/media/dvb-core/dvb_frontend.c:2939 Use-after-free read at 0xffff88805b2ccf3c (in kfence-#101): dvb_frontend_release+0x150/0x4d0 drivers/media/dvb-core/dvb_frontend.c:2939 __fput+0x418/0xa50 fs/file_table.c:512 task_work_run+0x1d9/0x270 kernel/task_work.c:233 get_signal+0x1181/0x12c0 kernel/signal.c:2818 arch_do_signal_or_restart+0xbb/0x860 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline] exit_to_user_mode_loop+0x10e/0x770 kernel/entry/common.c:101 __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:336 [inline] do_syscall_64+0x328/0x520 arch/x86/entry/syscall_64.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f kfence-#101: 0xffff88805b2ccf00-0xffff88805b2ccfd7, size=216, cache=kmalloc-256 allocated by task 1 on cpu 0 at 20.240909s (68.417034s ago): _kmalloc_noprof include/linux/slab.h:988 [inline] _kzalloc_noprof include/linux/slab.h:1309 [inline] dvb_register_device+0x309/0x1dd0 drivers/media/dvb-core/dvbdev.c:472 dvb_register_frontend+0x603/0x900 drivers/media/dvb-core/dvb_frontend.c:3074 vidtv_bridge_dvb_init drivers/media/test-drivers/vidtv/vidtv_bridge.c:438 [inline] vidtv_bridge_probe+0x9d5/0xf60 drivers/media/test-drivers/vidtv/vidtv_bridge.c:510 platform_probe+0xf9/0x190 drivers/base/platform.c:1507 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x254/0xae0 drivers/base/dd.c:706 __driver_probe_device+0x1e8/0x360 drivers/base/dd.c:868 driver_probe_device+0x4f/0x240 drivers/base/dd.c:898 __driver_attach+0x339/0x600 drivers/base/dd.c:1292 bus_for_each_dev+0x23b/0x2c0 drivers/base/bus.c:383 bus_add_driver+0x345/0x670 drivers/base/bus.c:763 driver_register+0x23a/0x320 drivers/base/driver.c:174 vidtv_bridge_init+0x3d/0x60 drivers/media/test-drivers/vidtv/vidtv_bridge.c:602 do_one_initcall+0x250/0x870 init/main.c:1353 do_initcall_level+0x10a/0x1a0 init/main.c:1415 do_initcalls+0x59/0xa0 init/main.c:1431 kernel_init_freeable+0x29d/0x3e0 init/main.c:1666 kernel_init+0x22/0x1d0 init/main.c:1556 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 5312 on cpu 0 at 88.624258s (0.077069s 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:2937 __fput+0x418/0xa50 fs/file_table.c:512 task_work_run+0x1d9/0x270 kernel/task_work.c:233 get_signal+0x1181/0x12c0 kernel/signal.c:2818 arch_do_signal_or_restart+0xbb/0x860 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline] exit_to_user_mode_loop+0x10e/0x770 kernel/entry/common.c:101 __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:336 [inline] do_syscall_64+0x328/0x520 arch/x86/entry/syscall_64.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f CPU: 0 UID: 0 PID: 5312 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:2939 Code: f9 4c 89 e7 4c 89 fe e8 9e c6 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 9e 02 00 00 <45> 8b 3f bf ff ff ff ff 44 89 fe e8 10 c2 b3 f9 41 83 ff ff 74 0a RSP: 0018:ffffc9000e13fb08 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff888035c0f000 RCX: ffffffff8238a657 RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffffffff9aa185b0 RBP: 0000000000000000 R08: ffffffff9aa185b7 R09: 1ffffffff35430b6 R10: dffffc0000000000 R11: fffffbfff35430b7 R12: ffff8880377a0d58 R13: ffff88803754b800 R14: dffffc0000000000 R15: ffff88805b2ccf3c FS: 0000555559163540(0000) GS:ffff88808c30a000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff88805b2ccf3c CR3: 0000000043791000 CR4: 0000000000352ef0 Call Trace: __fput+0x418/0xa50 fs/file_table.c:512 task_work_run+0x1d9/0x270 kernel/task_work.c:233 get_signal+0x1181/0x12c0 kernel/signal.c:2818 arch_do_signal_or_restart+0xbb/0x860 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline] exit_to_user_mode_loop+0x10e/0x770 kernel/entry/common.c:101 __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:336 [inline] do_syscall_64+0x328/0x520 arch/x86/entry/syscall_64.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f7e7e79e0d9 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:00007fff64b94338 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007fff64b94420 RCX: 00007f7e7e79e0d9 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 0000000000015152 R08: 0000000000000001 R09: 0000000000000000 R10: 00007f7e7e5ff02c R11: 0000000000000246 R12: 00007fff64b94460 R13: 00007f7e7ea25fac R14: 000000000001598e R15: 00007f7e7ea25fa0 ================================================================== ---------------- Code disassembly (best guess): 0: f9 stc 1: 4c 89 e7 mov %r12,%rdi 4: 4c 89 fe mov %r15,%rsi 7: e8 9e c6 fd ff call 0xfffdc6aa 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 9e 02 00 00 jne 0x2c8 * 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 c2 b3 f9 call 0xf9b3c24a 3a: 41 83 ff ff cmp $0xffffffff,%r15d 3e: 74 0a je 0x4a