On Thu, 18 Jul 2019, Andrey Konovalov wrote: > On Tue, Jul 16, 2019 at 4:17 PM Hillf Danton <hdan...@sina.com> wrote: > > > > > > Hello, > > > > On Tue, 16 Jul 2019 03:38:05 -0700 (PDT) > > > syzbot found the following crash on: > > > > > > HEAD commit: 6a3599ce usb-fuzzer: main usb gadget fuzzer driver > > > git tree: https://github.com/google/kasan.git usb-fuzzer > > > console output: https://syzkaller.appspot.com/x/log.txt?x=111fc400600000 > > > kernel config: https://syzkaller.appspot.com/x/.config?x=d90745bdf884fc0a > > > dashboard link: > > > https://syzkaller.appspot.com/bug?extid=4b3f8190f6e13b3efd74 > > > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10784148600000 > > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10d826a4600000 > > > > > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > > > Reported-by: syzbot+4b3f8190f6e13b3ef...@syzkaller.appspotmail.com > > > > > > usb 1-1: string descriptor 0 read error: -22 > > > usb 1-1: New USB device found, idVendor=077d, idProduct=627a, bcdDevice= > > > 0.10 > > > usb 1-1: New USB device strings: Mfr=63, Product=5, SerialNumber=1 > > > ------------[ cut here ]------------ > > > usb 1-1: BOGUS urb xfer, pipe 1 != type 3 > > > WARNING: CPU: 1 PID: 22 at drivers/usb/core/urb.c:477 > > > usb_submit_urb+0x1188/0x13b0 drivers/usb/core/urb.c:477 > > > Kernel panic - not syncing: panic_on_warn set ... > > > CPU: 1 PID: 22 Comm: kworker/1:1 Not tainted 5.2.0-rc6+ #14 > > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > > > Google 01/01/2011 > > > Workqueue: usb_hub_wq hub_event > > > Call Trace: > > > __dump_stack lib/dump_stack.c:77 [inline] > > > dump_stack+0xca/0x13e lib/dump_stack.c:113 > > > panic+0x292/0x6c9 kernel/panic.c:219 > > > __warn.cold+0x20/0x4b kernel/panic.c:576 > > > report_bug+0x262/0x2a0 lib/bug.c:186 > > > fixup_bug arch/x86/kernel/traps.c:179 [inline] > > > fixup_bug arch/x86/kernel/traps.c:174 [inline] > > > do_error_trap+0x12b/0x1e0 arch/x86/kernel/traps.c:272 > > > do_invalid_op+0x32/0x40 arch/x86/kernel/traps.c:291 > > > invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:986 > > > RIP: 0010:usb_submit_urb+0x1188/0x13b0 drivers/usb/core/urb.c:477 > > > Code: 4d 85 ed 74 2c e8 c8 69 e8 fd 4c 89 f7 e8 f0 c4 12 ff 41 89 d8 44 89 > > > e1 4c 89 ea 48 89 c6 48 c7 c7 60 3a 1a 86 e8 53 2e be fd <0f> 0b e9 20 f4 > > > ff ff e8 9c 69 e8 fd 4c 89 f2 48 b8 00 00 00 00 00 > > > RSP: 0018:ffff8881d9f96f58 EFLAGS: 00010282 > > > RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000000000 > > > RDX: 0000000000000000 RSI: ffffffff8127ef3d RDI: ffffed103b3f2ddd > > > RBP: ffff8881cf557590 R08: ffff8881d9f88000 R09: 0000000000000000 > > > R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 > > > R13: ffff8881d0c77000 R14: ffff8881d553cd20 R15: ffff8881d5123b00 > > > usb_start_wait_urb+0x108/0x2b0 drivers/usb/core/message.c:57 > > > usb_bulk_msg+0x228/0x550 drivers/usb/core/message.c:253 > > > shark_write_reg+0x1ef/0x2b0 drivers/media/radio/radio-shark2.c:88 > > > > Based on > > drivers/media/radio/radio-shark2.c:88 and > > drivers/usb/core/message.c:245 > > > > I say that the warning reported is bogus.
You have misunderstood the problem. drivers/usb/core/message.c:245 allows drivers to call usb_bulk_msg() when the target is actually an interrupt endpoint. The bug in this case is that drivers/media/radio/radio-shark2.c:88 calls usb_interrupt_msg() with an INTERRUPT pipe type when the target is actually a bulk endpoint. These are two different things. It can make sense to use an interrupt endpoint, especially if a bulk endpoint is not available. But the reverse does not make sense, because bulk endpoints do not provide the bandwidth guarantees that interrupt endpoints do. Alan Stern
