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Wed, 11 Nov 2026 21:56:39 -0800 (PST) Date: Wed, 11 Nov 2026 21:56:39 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6af55517.a0c627da.5d811.0010.GAE@google.com> Subject: [syzbot] [greybus?] [usb?] KASAN: slab-out-of-bounds Read in gb_operation_work From: syzbot To: elder@kernel.org, gregkh@linuxfoundation.org, greybus-dev@lists.linaro.org, johan@kernel.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-staging@lists.linux.dev, linux-usb@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 6628e7d4c6b2 Linux 7.4-rc1 git tree: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing console output: https://syzkaller.appspot.com/x/log.txt?x=109ac1a1580000 kernel config: https://syzkaller.appspot.com/x/.config?x=f9bf69220d319004 dashboard link: https://syzkaller.appspot.com/bug?extid=0b456664585fa81a47f6 compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=149ac1a1580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=150c9f8d580000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/d415be35d54e/disk-6628e7d4.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/69e49385122b/vmlinux-6628e7d4.xz kernel image: https://storage.googleapis.com/syzbot-assets/51be81fff25f/bzImage-6628e7d4.xz AI-generated root cause summary: In gb_connection_recv() (drivers/greybus/operation.c), the kernel verifies that the incoming buffer length is at least sizeof(struct gb_operation_msg_hdr), but fails to validate that the message header's claimed size (header.size, parsed as msg_size) is also at least sizeof(struct gb_operation_msg_hdr). When msg_size < sizeof(struct gb_operation_msg_hdr), gb_operation_create_incoming() subtracts the header size from msg_size, causing an unsigned integer underflow when calculating request_size. In gb_operation_message_alloc(), the payload size and header size wrap back around and kzalloc(msg_size) allocates an undersized buffer smaller than the header, leading to out-of-bounds reads when reading request_header->operation_id or a ZERO_SIZE_PTR dereference panic when msg_size is zero. full analysis: https://syzkaller.appspot.com/x/ai_root_cause?x=0b456664585fa81a47f6 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+0b456664585fa81a47f6@syzkaller.appspotmail.com greybus 1-svc: unexpected request 0x7f received (state 0) ================================================================== BUG: KASAN: slab-out-of-bounds in gb_operation_response_alloc drivers/greybus/operation.c:490 [inline] BUG: KASAN: slab-out-of-bounds in gb_operation_response_send drivers/greybus/operation.c:832 [inline] BUG: KASAN: slab-out-of-bounds in gb_operation_request_handle drivers/greybus/operation.c:252 [inline] BUG: KASAN: slab-out-of-bounds in gb_operation_work+0x8be/0x990 drivers/greybus/operation.c:280 Read of size 2 at addr ffff888105f0a642 by task kworker/u8:2/38 CPU: 1 UID: 0 PID: 38 Comm: kworker/u8:2 Not tainted syzkaller #0 PREEMPT(lazy) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/15/2026 Workqueue: greybus1:0 gb_operation_work Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x13d/0x4b0 mm/kasan/report.c:482 kasan_report+0xdf/0x1c0 mm/kasan/report.c:595 gb_operation_response_alloc drivers/greybus/operation.c:490 [inline] gb_operation_response_send drivers/greybus/operation.c:832 [inline] gb_operation_request_handle drivers/greybus/operation.c:252 [inline] gb_operation_work+0x8be/0x990 drivers/greybus/operation.c:280 process_one_work+0xac7/0x1b10 kernel/workqueue.c:3495 process_scheduled_works kernel/workqueue.c:3578 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3659 kthread+0x373/0x450 kernel/kthread.c:436 ret_from_fork+0x69f/0xc90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Allocated by task 28: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:409 [inline] __kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:426 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5531 [inline] __kmalloc_noprof+0x315/0x7e0 mm/slub.c:5556 _kmalloc_noprof include/linux/slab.h:995 [inline] _kzalloc_noprof include/linux/slab.h:1312 [inline] gb_operation_message_alloc+0x9b/0x2c0 drivers/greybus/operation.c:380 gb_operation_create_common+0x9f/0x710 drivers/greybus/operation.c:532 gb_operation_create_incoming drivers/greybus/operation.c:644 [inline] gb_connection_recv_request drivers/greybus/operation.c:926 [inline] gb_connection_recv+0x1dc/0x1050 drivers/greybus/operation.c:1063 greybus_data_rcvd+0x244/0x600 drivers/greybus/connection.c:89 cport_in_callback+0x1fb/0x280 drivers/greybus/es2.c:840 __usb_hcd_giveback_urb+0x38e/0x610 drivers/usb/core/hcd.c:1657 usb_hcd_giveback_urb+0x3ca/0x4a0 drivers/usb/core/hcd.c:1741 dummy_timer+0xdb5/0x3840 drivers/usb/gadget/udc/dummy_hcd.c:2051 __run_hrtimer kernel/time/hrtimer.c:2079 [inline] __hrtimer_run_queues+0x448/0x9a0 kernel/time/hrtimer.c:2136 hrtimer_run_softirq+0x1ca/0x360 kernel/time/hrtimer.c:2153 handle_softirqs+0x209/0xa00 kernel/softirq.c:669 __do_softirq kernel/softirq.c:703 [inline] invoke_softirq kernel/softirq.c:542 [inline] __irq_exit_rcu+0x17a/0x220 kernel/softirq.c:786 irq_exit_rcu+0x9/0x30 kernel/softirq.c:809 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline] sysvec_apic_timer_interrupt+0x8f/0xb0 arch/x86/kernel/apic/apic.c:1062 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 The buggy address belongs to the object at ffff888105f0a640 which belongs to the cache kmalloc-8 of size 8 The buggy address is located 2 bytes inside of allocated 3-byte region [ffff888105f0a640, ffff888105f0a643) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x105f0a flags: 0x200000000000000(node=0|zone=2) page_type: f5(slab) raw: 0200000000000000 ffff888100041500 dead000000000100 dead000000000122 raw: 0000000000000000 0000000000800080 00000000f5000000 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2c00(GFP_NOIO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 6490716744 set_page_owner include/linux/page_owner.h:33 [inline] post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1856 prep_new_page mm/page_alloc.c:1864 [inline] get_page_from_freelist+0xf4b/0x3440 mm/page_alloc.c:3935 __alloc_frozen_pages_noprof+0x299/0x2d50 mm/page_alloc.c:5444 alloc_slab_page mm/slub.c:3384 [inline] allocate_slab mm/slub.c:3499 [inline] new_slab+0xb1/0x6d0 mm/slub.c:3550 refill_objects+0xe3/0x410 mm/slub.c:7539 refill_sheaf mm/slub.c:2917 [inline] __pcs_replace_empty_main+0x35e/0x650 mm/slub.c:4811 alloc_from_pcs mm/slub.c:4887 [inline] slab_alloc_node mm/slub.c:5021 [inline] __do_kmalloc_node mm/slub.c:5530 [inline] __kmalloc_node_noprof+0x634/0x820 mm/slub.c:5543 _kmalloc_array_node_noprof include/linux/slab.h:1297 [inline] __blk_mq_realloc_hw_ctxs+0x579/0x820 block/blk-mq.c:4588 blk_mq_realloc_hw_ctxs block/blk-mq.c:4652 [inline] blk_mq_init_allocated_queue+0x36c/0x1500 block/blk-mq.c:4694 blk_mq_alloc_queue+0x1bd/0x290 block/blk-mq.c:4464 scsi_alloc_sdev+0x972/0xe90 drivers/scsi/scsi_scan.c:339 scsi_probe_and_add_lun+0x523/0x720 drivers/scsi/scsi_scan.c:1227 __scsi_scan_target+0x188/0x420 drivers/scsi/scsi_scan.c:1803 scsi_scan_channel drivers/scsi/scsi_scan.c:1893 [inline] scsi_scan_channel+0x142/0x1e0 drivers/scsi/scsi_scan.c:1868 scsi_scan_host_selected+0x2b3/0x380 drivers/scsi/scsi_scan.c:1922 do_scsi_scan_host+0x1f4/0x270 drivers/scsi/scsi_scan.c:2055 page_owner free stack trace missing Memory state around the buggy address: ffff888105f0a500: 06 fc fc fc 00 fc fc fc 00 fc fc fc 00 fc fc fc ffff888105f0a580: fa fc fc fc 06 fc fc fc 06 fc fc fc 06 fc fc fc >ffff888105f0a600: 06 fc fc fc 00 fc fc fc 03 fc fc fc fa fc fc fc ^ ffff888105f0a680: fa fc fc fc 00 fc fc fc fa fc fc fc 00 fc fc fc ffff888105f0a700: fa fc fc fc 05 fc fc fc 05 fc fc fc 05 fc fc fc ================================================================== --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup