On Sat, Dec 07, 2019 at 01:58:09AM +0100, Marek Marczykowski-Górecki wrote: > On Fri, Dec 06, 2019 at 02:12:08PM -0700, Shuah Khan wrote: > > On 12/6/19 1:57 PM, Marek Marczykowski-Górecki wrote: > > > On Fri, Dec 06, 2019 at 03:50:58PM +0900, Suwan Kim wrote: > > > > On Fri, Dec 06, 2019 at 04:24:06AM +0100, Marek Marczykowski-Górecki wrote: > > > > > Hello, > > > > > > > > > > I've hit an issue with recent 4.19 and 5.4 kernels. In short: if I > > > > > connect Yubikey 4 and use its CCID interface (for example `ykman oath > > > > > list` command), the client side hangs (100% reliably). After 60s I get a > > > > > message that a CPU hangs waiting for a spinlock (see below). > > > > > > > > > > I've bisected it to a ea44d190764b4422af ("usbip: Implement SG support > > > > > to vhci-hcd and stub driver") commit. Which indeed is also backported to > > > > > 4.19. > > > > > > > > > > Any idea what is going on here? I can easily provide more information, > > > > > if you tell me how to get it. > > > > > > > > > > > > > Hi, > > > > > > > > Thanks for reporting. Could you turn on lockdep and USBIP_DEBUG > > > > in kernel config and send dmesg log? It will be helpful to figure > > > > out lock dependency in vhci_hcd. > > > > > > Hmm, I've tried, but I don't see much more information there (see > > > below). I've just enabled PROVE_LOCKING and USBIP_DEBUG. Do I need to do > > > anything more, like some boot option? > > > > > > Also, this one (as the previous one) is from 4.19.84. Interestingly, on > > > 4.19.87 I don't get the message at all. > > > > > > Hmm, I've done also another test: got 4.19.84 with "usbip: Implement SG > > > support to vhci-hcd and stub driver" reverted and it still hangs... > > > > > > I'm going for another bisect round (4.19.81 works, 4.19.84 doesn't). > > > > Does 4.19.82 work? > > Yes, it does, or at least something after 4.19.82 works (9da271c1c). I've done bisect again and again got into the same commit. Most of the time I didn't get any message about the deadlock, it simply hanged. Full bisect log: git bisect start # good: [ef244c3088856cf048c77231653b4c92a7b2213c] Linux 4.19.81 git bisect good ef244c3088856cf048c77231653b4c92a7b2213c # bad: [c555efaf14026c7751fa68d87403a5eb5ae7dcaf] Linux 4.19.84 git bisect bad c555efaf14026c7751fa68d87403a5eb5ae7dcaf # good: [9da271c1cdc14839b694e23889a653c1ed0b5f8f] net: usb: lan78xx: Disable interrupts before calling generic_handle_irq() git bisect good 9da271c1cdc14839b694e23889a653c1ed0b5f8f # bad: [8181146cd7de890cdfdda68ddc3730250887d7fc] PCI: tegra: Enable Relaxed Ordering only for Tegra20 & Tegra30 git bisect bad 8181146cd7de890cdfdda68ddc3730250887d7fc # good: [8e6bf4bc3a88e4b84e5c4ec50143a71a61503336] mm: memcontrol: fix network errors from failing __GFP_ATOMIC charges git bisect good 8e6bf4bc3a88e4b84e5c4ec50143a71a61503336 # good: [0327c7818da27b018464c0b9f541c5d276c57172] can: flexcan: disable completely the ECC mechanism git bisect good 0327c7818da27b018464c0b9f541c5d276c57172 # good: [5e36cf8edb5812e378b57511263d1a0a9172eeb9] configfs: fix a deadlock in configfs_symlink() git bisect good 5e36cf8edb5812e378b57511263d1a0a9172eeb9 # good: [4f6c5200269998f0066e1bd4db931297b7b2b906] ALSA: usb-audio: Fix possible NULL dereference at create_yamaha_midi_quirk() git bisect good 4f6c5200269998f0066e1bd4db931297b7b2b906 # good: [502bd151448c2c76a927b26783e5538875c534ff] sched/fair: Fix low cpu usage with high throttling by removing expiration of cpu-local slices git bisect good 502bd151448c2c76a927b26783e5538875c534ff # good: [f865ae473c16fb2b8b8601fa04f4f6517ad557b3] usbip: Fix vhci_urb_enqueue() URB null transfer buffer error path git bisect good f865ae473c16fb2b8b8601fa04f4f6517ad557b3 # bad: [e2dd254bde5cdac24e7774584d6f3c2c61fe09e5] usbip: Implement SG support to vhci-hcd and stub driver git bisect bad e2dd254bde5cdac24e7774584d6f3c2c61fe09e5 # first bad commit: [e2dd254bde5cdac24e7774584d6f3c2c61fe09e5] usbip: Implement SG support to vhci-hcd and stub driver -- Best Regards, Marek Marczykowski-Górecki Invisible Things Lab A: Because it messes up the order in which people normally read text. Q: Why is top-posting such a bad thing?
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