** Description changed:
+
+ [DESCRIPTION]
+
+ When hotplugging a composite USB device that expose multiple interfaces
+ (such as a Yubikey NEO or Yubikey 4), libccid does not correctly de-
+ initialize the USB library when it skips over the non-CCID interface.
+
+ This subsequently results in pcscd (or, presumably, anything that loads
+ libccid, though I don't think anything else does) either using 100% CPU
+ or segfaulting when the device is unplugged.
+
+ This seems worthy of an SRU as it is an easily reproducible bug with a
+ simple, targeted fix.
+
+ [TEST CASE]
+
+ 1. Make sure pcscd is running (sudo systemctl start pcscd; possibly sudo
systemctl restart pcscd if a potentially fixed package has just been installed)
+ 2. Plug and then unplug a composite USB device that includes a CCID interface
(such as a Yubikey NEO)
+ 3. Observe that pcscd has crashed with a segfault (sudo systemctl status
pcscd)
+
+ [REGRESSION POTENTIAL]
+
+ The patch is quite narrow, and thus the potential for regression should
+ be limited. The new code adds calls to close_libusb_if_needed, which is
+ already written to be fairly conservative.
+
+ The worst case here is likely an unexpected call to libusb_exit, which
+ could cause libusb to get into an inconsistent state. However, in
+ practice the call seems quite safe, and the likelihood of regression
+ low.
+
+
+ ======
+ Original bug description:
+
In xenial, pcscd CPU utilization occasionally goes haywire:
- PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
- 27404 root 20 0 384264 4992 2228 S 100.3 0.0 75:39.03
/usr/sbin/pcscd --foreground --auto-exit
+ PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
+ 27404 root 20 0 384264 4992 2228 S 100.3 0.0 75:39.03
/usr/sbin/pcscd --foreground --auto-exit
I get this about once a day since installing xenial. I can't quite
connect it to any specific event on the system, it just seems to happen
sporadically -- fan turns on, I run top, and there it is again.
Never had this issue on same hardware incl. smartcard with trusty.
I wonder if it might be this? https://bugs.debian.org/cgi-
bin/bugreport.cgi?bug=718473
** Description changed:
-
- [DESCRIPTION]
+ [Impact]
When hotplugging a composite USB device that expose multiple interfaces
(such as a Yubikey NEO or Yubikey 4), libccid does not correctly de-
initialize the USB library when it skips over the non-CCID interface.
This subsequently results in pcscd (or, presumably, anything that loads
libccid, though I don't think anything else does) either using 100% CPU
or segfaulting when the device is unplugged.
This seems worthy of an SRU as it is an easily reproducible bug with a
simple, targeted fix.
- [TEST CASE]
+ [Test Case]
1. Make sure pcscd is running (sudo systemctl start pcscd; possibly sudo
systemctl restart pcscd if a potentially fixed package has just been installed)
2. Plug and then unplug a composite USB device that includes a CCID interface
(such as a Yubikey NEO)
3. Observe that pcscd has crashed with a segfault (sudo systemctl status
pcscd)
- [REGRESSION POTENTIAL]
+ [Regression Potential]
The patch is quite narrow, and thus the potential for regression should
be limited. The new code adds calls to close_libusb_if_needed, which is
already written to be fairly conservative.
The worst case here is likely an unexpected call to libusb_exit, which
could cause libusb to get into an inconsistent state. However, in
practice the call seems quite safe, and the likelihood of regression
low.
-
======
Original bug description:
In xenial, pcscd CPU utilization occasionally goes haywire:
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
27404 root 20 0 384264 4992 2228 S 100.3 0.0 75:39.03
/usr/sbin/pcscd --foreground --auto-exit
I get this about once a day since installing xenial. I can't quite
connect it to any specific event on the system, it just seems to happen
sporadically -- fan turns on, I run top, and there it is again.
Never had this issue on same hardware incl. smartcard with trusty.
I wonder if it might be this? https://bugs.debian.org/cgi-
bin/bugreport.cgi?bug=718473
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https://bugs.launchpad.net/bugs/1551897
Title:
Excessive CPU utilization
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