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2002:a05:6808:d4f:b0:485:7c46:b866 with SMTP id 5614622812f47-4b1f01b1d87mr1023979b6e.16.1786401570534; Mon, 10 Aug 2026 15:39:30 -0700 (PDT) Date: Mon, 10 Aug 2026 15:39:30 -0700 In-Reply-To: <6a7919c6.9c11d2ce.289b96.00de.GAE@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a7a5322.01d0871a.3a0d52.00ae.GAE@google.com> Subject: Re: [syzbot] [kernel?] KASAN: slab-use-after-free Write in bus_for_each_drv From: syzbot To: dakr@kernel.org, driver-core@lists.linux.dev, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, rafael@kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" syzbot has found a reproducer for the following issue on: HEAD commit: d58772d8520c Merge tag 'regmap-fix-v7.2-rc7' of git://git... git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=16e012c6580000 kernel config: https://syzkaller.appspot.com/x/.config?x=6ddb3079499f48cb dashboard link: https://syzkaller.appspot.com/bug?extid=9cb1ac7fce4944ba9165 compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1719d132580000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+9cb1ac7fce4944ba9165@syzkaller.appspotmail.com Need at least one configuration in g3. udc dummy_udc.0: failed to start g3: -22 configfs-gadget.g3 gadget.0: probe with driver configfs-gadget.g3 failed with error -22 ================================================================== BUG: KASAN: slab-use-after-free in knode_set_klist lib/klist.c:60 [inline] BUG: KASAN: slab-use-after-free in klist_release lib/klist.c:201 [inline] BUG: KASAN: slab-use-after-free in kref_put include/linux/kref.h:65 [inline] BUG: KASAN: slab-use-after-free in klist_dec_and_del+0x386/0x3d0 lib/klist.c:206 Write of size 8 at addr ffff88803fe920e0 by task syz-executor321/5936 CPU: 1 UID: 0 PID: 5936 Comm: syz-executor321 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description+0x55/0x1e0 mm/kasan/report.c:378 print_report+0x58/0x70 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 knode_set_klist lib/klist.c:60 [inline] klist_release lib/klist.c:201 [inline] kref_put include/linux/kref.h:65 [inline] klist_dec_and_del+0x386/0x3d0 lib/klist.c:206 klist_next+0xc3/0x2f0 lib/klist.c:386 next_driver drivers/base/bus.c:457 [inline] bus_for_each_drv+0x268/0x2f0 drivers/base/bus.c:499 __device_attach+0x2c7/0x450 drivers/base/dd.c:1098 device_initial_probe+0xa1/0xd0 drivers/base/dd.c:1153 bus_probe_device+0x12d/0x220 drivers/base/bus.c:620 device_add+0x7d7/0xb80 drivers/base/core.c:3772 usb_add_gadget+0x47d/0x700 drivers/usb/gadget/udc/core.c:1461 usb_add_gadget_udc_release+0x1a4/0x1f0 drivers/usb/gadget/udc/core.c:1517 dummy_udc_probe+0x6e1/0x7e0 drivers/usb/gadget/udc/dummy_hcd.c:1121 platform_probe+0xf9/0x190 drivers/base/platform.c:1439 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 device_driver_attach+0xe0/0x1d0 drivers/base/dd.c:1203 bind_store+0x1d3/0x220 drivers/base/bus.c:267 kernfs_fop_write_iter+0x3a5/0x540 fs/kernfs/file.c:345 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x61e/0xbb0 fs/read_write.c:687 ksys_write+0x156/0x270 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f453d1641de Code: 08 0f 85 f5 e2 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 90 41 57 41 56 4d 89 c6 41 55 4d 89 cd 41 54 55 53 48 83 ec 08 RSP: 002b:00007f453d106f98 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f453d1076c0 RCX: 00007f453d1641de RDX: 000000000000000b RSI: 00007f453d1ad1b9 RDI: 0000000000000003 RBP: 0000000000000005 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003 R13: 0000000000000010 R14: 00007ffca4345660 R15: 00007ffca4345748 Allocated by task 5940: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __kmalloc_cache_noprof+0x3d2/0x6b0 mm/slub.c:5489 _kmalloc_noprof include/linux/slab.h:988 [inline] _kzalloc_noprof include/linux/slab.h:1309 [inline] bus_add_driver+0x165/0x670 drivers/base/bus.c:747 driver_register+0x23a/0x320 drivers/base/driver.c:174 usb_gadget_register_driver_owner+0xf9/0x270 drivers/usb/gadget/udc/core.c:1752 gadget_dev_desc_UDC_store+0x1c9/0x2f0 drivers/usb/gadget/configfs.c:300 flush_write_buffer fs/configfs/file.c:207 [inline] configfs_write_iter+0x33a/0x430 fs/configfs/file.c:229 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x61e/0xbb0 fs/read_write.c:687 ksys_write+0x156/0x270 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 5940: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2677 [inline] slab_free mm/slub.c:6377 [inline] kfree+0x1c5/0x6c0 mm/slub.c:6692 kobject_cleanup lib/kobject.c:689 [inline] kobject_release lib/kobject.c:720 [inline] kref_put include/linux/kref.h:65 [inline] kobject_put+0x222/0x550 lib/kobject.c:737 bus_remove_driver+0x248/0x320 drivers/base/bus.c:834 usb_gadget_register_driver_owner+0x223/0x270 drivers/usb/gadget/udc/core.c:1774 gadget_dev_desc_UDC_store+0x1c9/0x2f0 drivers/usb/gadget/configfs.c:300 flush_write_buffer fs/configfs/file.c:207 [inline] configfs_write_iter+0x33a/0x430 fs/configfs/file.c:229 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x61e/0xbb0 fs/read_write.c:687 ksys_write+0x156/0x270 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88803fe92000 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 224 bytes inside of freed 512-byte region [ffff88803fe92000, ffff88803fe92200) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x3fe90 head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0x80000000000040(head|node=0|zone=1) page_type: f5(slab) raw: 0080000000000040 ffff88813ffb3c80 dead000000000100 dead000000000122 raw: 0000000000000000 0000000800100010 00000000f5000000 0000000000000000 head: 0080000000000040 ffff88813ffb3c80 dead000000000100 dead000000000122 head: 0000000000000000 0000000800100010 00000000f5000000 0000000000000000 head: 0080000000000002 ffffffffffffff01 00000000ffffffff 00000000ffffffff head: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000004 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5633, tgid 5633 (syz-executor), ts 102640041714, free_ts 80262861649 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1859 prep_new_page mm/page_alloc.c:1867 [inline] get_page_from_freelist+0x262a/0x26a0 mm/page_alloc.c:3946 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5304 alloc_slab_page mm/slub.c:3266 [inline] allocate_slab+0x79/0x5e0 mm/slub.c:3380 new_slab mm/slub.c:3426 [inline] refill_objects+0x2d8/0x350 mm/slub.c:7310 refill_sheaf mm/slub.c:2804 [inline] __pcs_replace_empty_main+0x330/0x690 mm/slub.c:4675 alloc_from_pcs mm/slub.c:4773 [inline] slab_alloc_node mm/slub.c:4905 [inline] __kmalloc_cache_noprof+0x468/0x6b0 mm/slub.c:5485 _kmalloc_noprof include/linux/slab.h:988 [inline] _kzalloc_noprof include/linux/slab.h:1309 [inline] mca_alloc net/ipv6/mcast.c:871 [inline] __ipv6_dev_mc_inc+0x447/0xa40 net/ipv6/mcast.c:961 ipv6_add_dev+0xe83/0x1400 net/ipv6/addrconf.c:475 addrconf_notify+0x771/0x1050 net/ipv6/addrconf.c:3685 notifier_call_chain+0x1a5/0x3d0 kernel/notifier.c:85 call_netdevice_notifiers_extack net/core/dev.c:2288 [inline] call_netdevice_notifiers net/core/dev.c:2302 [inline] register_netdevice+0x18c0/0x1ed0 net/core/dev.c:11484 __ip_tunnel_create+0x3e8/0x550 net/ipv4/ip_tunnel.c:268 ip_tunnel_init_net+0x2e5/0x820 net/ipv4/ip_tunnel.c:1150 ops_init+0x35d/0x5d0 net/core/net_namespace.c:137 setup_net+0x118/0x350 net/core/net_namespace.c:446 page last free pid 5564 tgid 5564 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1406 [inline] __free_frozen_pages+0x10e7/0x11c0 mm/page_alloc.c:2950 __slab_free+0x252/0x2a0 mm/slub.c:5741 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4584 [inline] slab_alloc_node mm/slub.c:4917 [inline] __kmalloc_cache_noprof+0x351/0x6b0 mm/slub.c:5485 _kmalloc_noprof include/linux/slab.h:988 [inline] single_open+0x5a/0x240 fs/seq_file.c:576 do_dentry_open+0x849/0x1420 fs/open.c:947 vfs_open+0x3b/0x350 fs/open.c:1052 do_open fs/namei.c:4700 [inline] path_openat+0x2e60/0x3850 fs/namei.c:4863 do_file_open+0x23e/0x4a0 fs/namei.c:4892 do_sys_openat2+0x115/0x200 fs/open.c:1368 do_sys_open fs/open.c:1374 [inline] __do_sys_openat fs/open.c:1390 [inline] __se_sys_openat fs/open.c:1385 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1385 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff88803fe91f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88803fe92000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88803fe92080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88803fe92100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88803fe92180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== --- If you want syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing.