On Mon, 12 Dec 2016, Alan Stern wrote: > On Mon, 12 Dec 2016, Dmitry Vyukov wrote: > > > On Mon, Dec 12, 2016 at 10:05 PM, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > > > On Mon, 12 Dec 2016, Andrey Konovalov wrote: > > > > > >> Hi! > > >> > > >> While running the syzkaller fuzzer I've got the following error report. > > >> > > >> On commit 3c49de52d5647cda8b42c4255cf8a29d1e22eff5 (Dev 2). > > >> > > >> WARNING: CPU: 2 PID: 865 at fs/sysfs/dir.c:31 sysfs_warn_dup+0x8a/0xa0 > > >> gadgetfs: disconnected > > >> sysfs: cannot create duplicate filename > > >> '/devices/platform/dummy_hcd.0/usb2/2-1/2-1:64.0/ep_05' > > >> Kernel panic - not syncing: panic_on_warn set ... > > > > > > I suppose we could check for USB devices that claim to have two > > > endpoints with the same address. But is it really worthwhile? A > > > kernel warning isn't so bad when you're dealing with buggy device > > > firmware. > > > > We need a clear distinction between what is a bug in kernel source > > code and what is incorrect user-space code. Otherwise no automated > > testing is possible. WARNING means bug in kernel source code. > > I don't necessarily agree with that. Is it documented anywhere? > > > If it is > > not a bug in kernel source code, then it must not produce a WARNING. What about a memory allocation failure? The memory management part of the kernel produces a WARNING message if an allocation fails and the caller did not specify __GFP_NOWARN. There is no way for a driver to guarantee that a memory allocation request will succeed -- failure is always an option. But obviously memory allocation failures are not bugs in the kernel. Are you saying that mm/page_alloc.c:warn_alloc() should produce something other than a WARNING? Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
