el0t_64_sync_handler+0x84/0x108 arch/arm64/kernel/entry-common.c:762 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600 iommufd_mock iommufd_mock0: Adding to iommu group 0 ================================================================== BUG: KASAN: slab-use-after-free in software_node_notify_remove+0x1c4/0x1c8 drivers/base/swnode.c:1108 Read of size 1 at addr ffff0000ce639108 by task syz.1.110/7013 CPU: 1 UID: 0 PID: 7013 Comm: syz.1.110 Not tainted 6.15.0-rc1-syzkaller-g2fe2b96c3818 #0 PREEMPT Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call trace: show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:466 (C) __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0xe4/0x150 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:408 [inline] print_report+0x198/0x550 mm/kasan/report.c:521 kasan_report+0xd8/0x138 mm/kasan/report.c:634 __asan_report_load1_noabort+0x20/0x2c mm/kasan/report_generic.c:378 software_node_notify_remove+0x1c4/0x1c8 drivers/base/swnode.c:1108 device_platform_notify_remove drivers/base/core.c:2387 [inline] device_del+0x498/0x828 drivers/base/core.c:3858 device_unregister+0x2c/0xcc drivers/base/core.c:3896 mock_dev_destroy drivers/iommu/iommufd/selftest.c:960 [inline] iommufd_test_mock_domain drivers/iommu/iommufd/selftest.c:1022 [inline] iommufd_test+0x28d4/0x4bbc drivers/iommu/iommufd/selftest.c:1866 iommufd_fops_ioctl+0x5d8/0x734 drivers/iommu/iommufd/main.c:419 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl fs/ioctl.c:892 [inline] __arm64_sys_ioctl+0x14c/0x1c4 fs/ioctl.c:892 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:744 el0t_64_sync_handler+0x84/0x108 arch/arm64/kernel/entry-common.c:762 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600 Allocated by task 7013: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x40/0x78 mm/kasan/common.c:68 kasan_save_alloc_info+0x40/0x50 mm/kasan/generic.c:562 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0xac/0xc4 mm/kasan/common.c:394 kasan_kmalloc include/linux/kasan.h:260 [inline] __kmalloc_cache_noprof+0x2cc/0x428 mm/slub.c:4362 kmalloc_noprof include/linux/slab.h:905 [inline] kzalloc_noprof include/linux/slab.h:1039 [inline] swnode_register+0x70/0x490 drivers/base/swnode.c:790 fwnode_create_software_node+0x190/0x1e8 drivers/base/swnode.c:949 device_create_managed_software_node+0xdc/0x1f8 drivers/base/swnode.c:1060 mock_dev_create drivers/iommu/iommufd/selftest.c:942 [inline] iommufd_test_mock_domain drivers/iommu/iommufd/selftest.c:989 [inline] iommufd_test+0x2648/0x4bbc drivers/iommu/iommufd/selftest.c:1866 iommufd_fops_ioctl+0x5d8/0x734 drivers/iommu/iommufd/main.c:419 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl fs/ioctl.c:892 [inline] __arm64_sys_ioctl+0x14c/0x1c4 fs/ioctl.c:892 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:744 el0t_64_sync_handler+0x84/0x108 arch/arm64/kernel/entry-common.c:762 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600 Freed by task 7013: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x40/0x78 mm/kasan/common.c:68 kasan_save_free_info+0x54/0x6c mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x64/0x8c mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2389 [inline] slab_free mm/slub.c:4646 [inline] kfree+0x180/0x478 mm/slub.c:4845 software_node_release+0x1dc/0x244 drivers/base/swnode.c:775 kobject_cleanup lib/kobject.c:689 [inline] kobject_release lib/kobject.c:720 [inline] kref_put include/linux/kref.h:65 [inline] kobject_put+0x2a8/0x41c lib/kobject.c:737 software_node_notify_remove+0x168/0x1c8 drivers/base/swnode.c:1106 device_platform_notify_remove drivers/base/core.c:2387 [inline] device_del+0x498/0x828 drivers/base/core.c:3858 device_unregister+0x2c/0xcc drivers/base/core.c:3896 mock_dev_destroy drivers/iommu/iommufd/selftest.c:960 [inline] iommufd_test_mock_domain drivers/iommu/iommufd/selftest.c:1022 [inline] iommufd_test+0x28d4/0x4bbc drivers/iommu/iommufd/selftest.c:1866 iommufd_fops_ioctl+0x5d8/0x734 drivers/iommu/iommufd/main.c:419 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl fs/ioctl.c:892 [inline] __arm64_sys_ioctl+0x14c/0x1c4 fs/ioctl.c:892 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:744 el0t_64_sync_handler+0x84/0x108 arch/arm64/kernel/entry-common.c:762 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600 The buggy address belongs to the object at ffff0000ce639000 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 264 bytes inside of freed 512-byte region [ffff0000ce639000, ffff0000ce639200) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10e638 head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 anon flags: 0x5ffc00000000040(head|node=0|zone=2|lastcpupid=0x7ff) page_type: f5(slab) raw: 05ffc00000000040 ffff0000c0001c80 0000000000000000 dead000000000001 raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 05ffc00000000040 ffff0000c0001c80 0000000000000000 dead000000000001 head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 05ffc00000000002 fffffdffc3398e01 00000000ffffffff 00000000ffffffff head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000004 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff0000ce639000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff0000ce639080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff0000ce639100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff0000ce639180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff0000ce639200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ================================================================== ------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: CPU: 1 PID: 7013 at lib/refcount.c:28 refcount_warn_saturate+0x1c8/0x20c lib/refcount.c:28 Modules linked in: CPU: 1 UID: 0 PID: 7013 Comm: syz.1.110 Tainted: G B 6.15.0-rc1-syzkaller-g2fe2b96c3818 #0 PREEMPT Tainted: [B]=BAD_PAGE Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : refcount_warn_saturate+0x1c8/0x20c lib/refcount.c:28 lr : refcount_warn_saturate+0x1c8/0x20c lib/refcount.c:28 sp : ffff80009fc07750 x29: ffff80009fc07750 x28: ffff80009fc07c20 x27: 1ffff00013f80f0c x26: 1fffe00019cc7207 x25: dfff800000000000 x24: 0000000000000000 x23: dfff800000000000 x22: ffff0000ce63903c x21: 0000000000000003 x20: ffff0000ce639038 x19: ffff80009341c000 x18: 0000000000000008 x17: 0000000000000000 x16: ffff8000833376cc x15: 0000000000000001 x14: 1fffe000366e2322 x13: 0000000000000000 x12: 0000000000000000 x11: 0000000000000002 x10: 0000000000ff0100 x9 : 890ff997a9247400 x8 : 890ff997a9247400 x7 : 0000000000000001 x6 : 0000000000000001 x5 : ffff80009fc06ed8 x4 : ffff800090035280 x3 : ffff8000807526f0 x2 : 0000000000000001 x1 : 0000000100000000 x0 : 0000000000000000 Call trace: refcount_warn_saturate+0x1c8/0x20c lib/refcount.c:28 (P) __refcount_sub_and_test include/linux/refcount.h:400 [inline] __refcount_dec_and_test include/linux/refcount.h:432 [inline] refcount_dec_and_test include/linux/refcount.h:450 [inline] kref_put include/linux/kref.h:64 [inline] kobject_put+0x1a0/0x41c lib/kobject.c:737 software_node_notify_remove+0x1ac/0x1c8 drivers/base/swnode.c:1110 device_platform_notify_remove drivers/base/core.c:2387 [inline] device_del+0x498/0x828 drivers/base/core.c:3858 device_unregister+0x2c/0xcc drivers/base/core.c:3896 mock_dev_destroy drivers/iommu/iommufd/selftest.c:960 [inline] iommufd_test_mock_domain drivers/iommu/iommufd/selftest.c:1022 [inline] iommufd_test+0x28d4/0x4bbc drivers/iommu/iommufd/selftest.c:1866 iommufd_fops_ioctl+0x5d8/0x734 drivers/iommu/iommufd/main.c:419 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl fs/ioctl.c:892 [inline] __arm64_sys_ioctl+0x14c/0x1c4 fs/ioctl.c:892 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:744 el0t_64_sync_handler+0x84/0x108 arch/arm64/kernel/entry-common.c:762 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600 irq event stamp: 891 hardirqs last enabled at (891): [] raw_spin_rq_unlock_irq kernel/sched/sched.h:1525 [inline] hardirqs last enabled at (891): [] finish_lock_switch+0xbc/0x1e4 kernel/sched/core.c:5130 hardirqs last disabled at (890): [] __schedule+0x328/0x2c80 kernel/sched/core.c:6671 softirqs last enabled at (710): [] softirq_handle_end kernel/softirq.c:425 [inline] softirqs last enabled at (710): [] handle_softirqs+0xb44/0xd34 kernel/softirq.c:607 softirqs last disabled at (579): [] __do_softirq+0x14/0x20 kernel/softirq.c:613 ---[ end trace 0000000000000000 ]---