EXT4-fs (loop1): Couldn't mount because of unsupported optional features (fffc1829) EXT4-fs (loop1): couldn't mount as ext3 due to feature incompatibilities ================================================================== BUG: KASAN: use-after-free in dvb_device_open+0xd4/0x388 drivers/media/dvb-core/dvbdev.c:99 Read of size 8 at addr ffff0000d3764218 by task syz.1.197/5430 CPU: 1 PID: 5430 Comm: syz.1.197 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Call trace: dump_backtrace+0x1c0/0x1ec arch/arm64/kernel/stacktrace.c:158 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165 __dump_stack+0x30/0x40 lib/dump_stack.c:88 dump_stack_lvl+0xf4/0x15c lib/dump_stack.c:106 print_address_description+0x88/0x218 mm/kasan/report.c:316 print_report+0x50/0x68 mm/kasan/report.c:420 kasan_report+0xa8/0xfc mm/kasan/report.c:524 __asan_report_load8_noabort+0x2c/0x38 mm/kasan/report_generic.c:351 dvb_device_open+0xd4/0x388 drivers/media/dvb-core/dvbdev.c:99 chrdev_open+0x3d4/0x518 fs/char_dev.c:414 do_dentry_open+0x72c/0xf98 fs/open.c:882 vfs_open+0x7c/0x90 fs/open.c:1015 do_open fs/namei.c:3634 [inline] path_openat+0x1f8c/0x26bc fs/namei.c:3791 do_filp_open+0x194/0x384 fs/namei.c:3818 do_sys_openat2+0x134/0x3f4 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] __arm64_sys_openat+0x118/0x14c fs/open.c:1347 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 Allocated by task 1: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4c/0x80 mm/kasan/common.c:53 kasan_save_alloc_info+0x24/0x30 mm/kasan/generic.c:505 ____kasan_kmalloc mm/kasan/common.c:375 [inline] __kasan_kmalloc+0xa0/0xb8 mm/kasan/common.c:384 kasan_kmalloc include/linux/kasan.h:211 [inline] kmalloc_trace+0x7c/0x94 mm/slab_common.c:1031 kmalloc include/linux/slab.h:563 [inline] kzalloc include/linux/slab.h:699 [inline] dvb_register_device+0x1a0/0x17a8 drivers/media/dvb-core/dvbdev.c:478 dvb_register_frontend+0x4c0/0x720 drivers/media/dvb-core/dvb_frontend.c:3035 vidtv_bridge_dvb_init drivers/media/test-drivers/vidtv/vidtv_bridge.c:438 [inline] vidtv_bridge_probe+0x9ac/0xe34 drivers/media/test-drivers/vidtv/vidtv_bridge.c:510 platform_probe+0x13c/0x1b4 drivers/base/platform.c:1400 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x39c/0xacc drivers/base/dd.c:639 __driver_probe_device+0x1c8/0x358 drivers/base/dd.c:805 driver_probe_device+0x78/0x324 drivers/base/dd.c:835 __driver_attach+0x3bc/0x60c drivers/base/dd.c:1221 bus_for_each_dev+0x148/0x1d0 drivers/base/bus.c:303 driver_attach+0x4c/0x5c drivers/base/dd.c:1238 bus_add_driver+0x2d8/0x554 drivers/base/bus.c:620 driver_register+0x200/0x378 drivers/base/driver.c:246 __platform_driver_register+0x6c/0x80 drivers/base/platform.c:867 vidtv_bridge_init+0x4c/0x8c drivers/media/test-drivers/vidtv/vidtv_bridge.c:602 do_one_initcall+0x278/0x9e0 init/main.c:1309 do_initcall_level+0x154/0x214 init/main.c:1382 do_initcalls+0x58/0xac init/main.c:1398 do_basic_setup+0x8c/0xa0 init/main.c:1417 kernel_init_freeable+0x35c/0x4f0 init/main.c:1637 kernel_init+0x24/0x1d8 init/main.c:1525 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:850 Freed by task 5393: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4c/0x80 mm/kasan/common.c:53 kasan_save_free_info+0x38/0x5c mm/kasan/generic.c:516 ____kasan_slab_free+0x148/0x1b0 mm/kasan/common.c:237 __kasan_slab_free+0x18/0x28 mm/kasan/common.c:245 kasan_slab_free include/linux/kasan.h:177 [inline] slab_free_hook mm/slub.c:1729 [inline] slab_free_freelist_hook+0x16c/0x1e8 mm/slub.c:1755 slab_free mm/slub.c:3687 [inline] __kmem_cache_free+0xbc/0x218 mm/slub.c:3700 kfree+0xd0/0x1a8 mm/slab_common.c:988 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+0x2dc/0x388 drivers/media/dvb-core/dvbdev.c:113 chrdev_open+0x3d4/0x518 fs/char_dev.c:414 do_dentry_open+0x72c/0xf98 fs/open.c:882 vfs_open+0x7c/0x90 fs/open.c:1015 do_open fs/namei.c:3634 [inline] path_openat+0x1f8c/0x26bc fs/namei.c:3791 do_filp_open+0x194/0x384 fs/namei.c:3818 do_sys_openat2+0x134/0x3f4 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] __arm64_sys_openat+0x118/0x14c fs/open.c:1347 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 The buggy address belongs to the object at ffff0000d3764200 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 24 bytes inside of 256-byte region [ffff0000d3764200, ffff0000d3764300) The buggy address belongs to the physical page: page:00000000b07114e9 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x113764 head:00000000b07114e9 order:1 compound_mapcount:0 compound_pincount:0 flags: 0x5ffc00000010200(slab|head|node=0|zone=2|lastcpupid=0x7ff) raw: 05ffc00000010200 fffffc00034ba800 dead000000000002 ffff0000c0002480 raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff0000d3764100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff0000d3764180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff0000d3764200: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff0000d3764280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff0000d3764300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ================================================================== ------------[ cut here ]------------ refcount_t: addition on 0; use-after-free. WARNING: CPU: 1 PID: 5430 at lib/refcount.c:25 refcount_warn_saturate+0x134/0x1f8 lib/refcount.c:25 Modules linked in: CPU: 1 PID: 5430 Comm: syz.1.197 Tainted: G B syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 pstate: 62400005 (nZCv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--) pc : refcount_warn_saturate+0x134/0x1f8 lib/refcount.c:25 lr : refcount_warn_saturate+0x134/0x1f8 lib/refcount.c:25 sp : ffff8000211e75c0 x29: ffff8000211e75c0 x28: ffff0000da6aa7a8 x27: dfff800000000000 x26: ffff0000d3923000 x25: dfff800000000000 x24: 1fffe0001a6ec843 x23: 0000000000000000 x22: ffff0000d3764210 x21: ffff0000d2ccf930 x20: ffff0000d3764210 x19: ffff800017c11000 x18: 0000000000000000 x17: 0000000000000000 x16: ffff80000804389c x15: 0000000000000002 x14: 0000000000000001 x13: 1ffff0000423ce08 x12: 0000000000080000 x11: 000000000002d6f4 x10: ffff8000231bc000 x9 : b9ed1c0e7cbe6900 x8 : b9ed1c0e7cbe6900 x7 : 0000000000000001 x6 : 0000000000000001 x5 : ffff8000211e7058 x4 : ffff800015324ea0 x3 : ffff80000831a204 x2 : 0000000000000001 x1 : 0000000100000000 x0 : 0000000000000000 Call trace: refcount_warn_saturate+0x134/0x1f8 lib/refcount.c:25 __refcount_add include/linux/refcount.h:-1 [inline] __refcount_inc include/linux/refcount.h:250 [inline] refcount_inc include/linux/refcount.h:267 [inline] kref_get include/linux/kref.h:45 [inline] dvb_device_get drivers/media/dvb-core/dvbdev.c:631 [inline] dvb_device_open+0x328/0x388 drivers/media/dvb-core/dvbdev.c:106 chrdev_open+0x3d4/0x518 fs/char_dev.c:414 do_dentry_open+0x72c/0xf98 fs/open.c:882 vfs_open+0x7c/0x90 fs/open.c:1015 do_open fs/namei.c:3634 [inline] path_openat+0x1f8c/0x26bc fs/namei.c:3791 do_filp_open+0x194/0x384 fs/namei.c:3818 do_sys_openat2+0x134/0x3f4 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] __arm64_sys_openat+0x118/0x14c fs/open.c:1347 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140 do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204 el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 irq event stamp: 3411 hardirqs last enabled at (3411): [] raw_spin_rq_unlock_irq kernel/sched/sched.h:1374 [inline] hardirqs last enabled at (3411): [] __schedule+0xed0/0x1b0c kernel/sched/core.c:6568 hardirqs last disabled at (3410): [] __schedule+0x298/0x1b0c kernel/sched/core.c:6460 softirqs last enabled at (2862): [] local_bh_enable+0x10/0x34 include/linux/bottom_half.h:32 softirqs last disabled at (2860): [] local_bh_disable+0x10/0x34 include/linux/bottom_half.h:19 ---[ end trace 0000000000000000 ]--- ------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: CPU: 1 PID: 5430 at lib/refcount.c:28 refcount_warn_saturate+0x154/0x1f8 lib/refcount.c:28 Modules linked in: CPU: 1 PID: 5430 Comm: syz.1.197 Tainted: G B W syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 pstate: 62400005 (nZCv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--) pc : refcount_warn_saturate+0x154/0x1f8 lib/refcount.c:28 lr : refcount_warn_saturate+0x154/0x1f8 lib/refcount.c:28 sp : ffff8000211e79b0 x29: ffff8000211e79b0 x28: ffff0000cfe13d60 x27: 1fffe0001b4d54f5 x26: ffff0000da6aa7a8 x25: ffff0000d2ddd000 x24: ffff0000d3764200 x23: dfff800000000000 x22: 0000000000000000 x21: 00000000c0000000 x20: ffff0000d3764210 x19: ffff800017c11000 x18: 0000000000000000 x17: 0000000000000000 x16: ffff80000804389c x15: 0000000000000002 x14: 0000000000000001 x13: 1ffff0000423ce84 x12: 0000000000080000 x11: 000000000000ca2c x10: ffff8000231bc000 x9 : b9ed1c0e7cbe6900 x8 : b9ed1c0e7cbe6900 x7 : 0000000000000001 x6 : 0000000000000001 x5 : ffff8000211e7438 x4 : ffff800015324ea0 x3 : ffff80000831a204 x2 : 0000000000000001 x1 : 0000000100000000 x0 : 0000000000000000 Call trace: refcount_warn_saturate+0x154/0x1f8 lib/refcount.c:28 __refcount_sub_and_test include/linux/refcount.h:283 [inline] __refcount_dec_and_test include/linux/refcount.h:315 [inline] refcount_dec_and_test include/linux/refcount.h:333 [inline] kref_put include/linux/kref.h:64 [inline] dvb_device_put drivers/media/dvb-core/dvbdev.c:640 [inline] dvb_generic_release+0x16c/0x1e0 drivers/media/dvb-core/dvbdev.c:173 dvb_frontend_release+0x114/0x400 drivers/media/dvb-core/dvb_frontend.c:2898 __fput+0x1bc/0x7b8 fs/file_table.c:320 ____fput+0x20/0x30 fs/file_table.c:348 task_work_run+0x1ec/0x278 kernel/task_work.c:203 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] do_notify_resume+0x1fa0/0x2aa4 arch/arm64/kernel/signal.c:1151 prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:137 [inline] exit_to_user_mode arch/arm64/kernel/entry-common.c:142 [inline] el0_svc+0x98/0x128 arch/arm64/kernel/entry-common.c:638 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585 irq event stamp: 3411 hardirqs last enabled at (3411): [] raw_spin_rq_unlock_irq kernel/sched/sched.h:1374 [inline] hardirqs last enabled at (3411): [] __schedule+0xed0/0x1b0c kernel/sched/core.c:6568 hardirqs last disabled at (3410): [] __schedule+0x298/0x1b0c kernel/sched/core.c:6460 softirqs last enabled at (2862): [] local_bh_enable+0x10/0x34 include/linux/bottom_half.h:32 softirqs last disabled at (2860): [] local_bh_disable+0x10/0x34 include/linux/bottom_half.h:19 ---[ end trace 0000000000000000 ]---