From: Robert Munteanu <firstname.lastname@example.org> To: Greg Kroah-Hartman <email@example.com> Cc: Mathias Nyman <firstname.lastname@example.org>, email@example.com, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org Subject: Re: Regression: plugging in USB scanner breaks all USB functionality Date: Fri, 03 Dec 2021 16:33:23 +0100 [thread overview] Message-ID: <email@example.com> (raw) In-Reply-To: <YajjhwMDkX2CyrQD@kroah.com> On Thu, 2021-12-02 at 16:17 +0100, Greg Kroah-Hartman wrote: > On Thu, Dec 02, 2021 at 03:55:44PM +0100, Robert Munteanu wrote: > > Hi, > > > > After updating from kernel 5.14.11 to 5.14.14 I am seeing the > > following > > problem: > > Can you run 'git bisect' between those kernel versions to get the > offending commit located? It shouldn't take that long as there's not a > lot of changes there. A full bisect run, as suspected in other messages, results in e54abefe703ab7c4e5983e889babd1447738ca42 is the first bad commit commit e54abefe703ab7c4e5983e889babd1447738ca42 Author: Pavankumar Kondeti <firstname.lastname@example.org> Date: Fri Oct 8 12:25:46 2021 +0300 xhci: Fix command ring pointer corruption while aborting a command commit ff0e50d3564f33b7f4b35cadeabd951d66cfc570 upstream. The command ring pointer is located at [6:63] bits of the command ring control register (CRCR). All the control bits like command stop, abort are located at [0:3] bits. While aborting a command, we read the CRCR and set the abort bit and write to the CRCR. The read will always give command ring pointer as all zeros. So we essentially write only the control bits. Since we split the 64 bit write into two 32 bit writes, there is a possibility of xHC command ring stopped before the upper dword (all zeros) is written. If that happens, xHC updates the upper dword of its internal command ring pointer with all zeros. Next time, when the command ring is restarted, we see xHC memory access failures. Fix this issue by only writing to the lower dword of CRCR where all control bits are located. Cc: email@example.com Signed-off-by: Pavankumar Kondeti <firstname.lastname@example.org> Signed-off-by: Mathias Nyman <email@example.com> Link: https://firstname.lastname@example.org Signed-off-by: Greg Kroah-Hartman <email@example.com> drivers/usb/host/xhci-ring.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) I will try the patch linked by Matias as soon as the openSUSE kernel build is complete. Thanks, Robert
next prev parent reply other threads:[~2021-12-03 15:33 UTC|newest] Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-12-02 14:55 Robert Munteanu 2021-12-02 15:13 ` Thorsten Leemhuis 2021-12-03 17:24 ` Regression: plugging in USB scanner breaks all USB functionality #forregzbot Thorsten Leemhuis 2021-12-04 10:03 ` Greg KH 2021-12-04 10:26 ` Regression: plugging in USB scanner breaks all USB functionality Thorsten Leemhuis 2021-12-04 10:44 ` Greg KH 2021-12-04 11:06 ` Thorsten Leemhuis 2021-12-02 15:17 ` Greg Kroah-Hartman 2021-12-03 15:33 ` Robert Munteanu [this message] 2021-12-03 10:57 ` Mathias Nyman 2021-12-03 11:36 ` Takashi Iwai 2021-12-03 16:22 ` Robert Munteanu
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