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Description of problem: The vmmouse_detect utility enters a SIGSEGV loop on physical systems with the package installed. An strace of the process shows the following: 7104 12:12:42.823562 readlink("/sys/devices/virtual/input/input13/event13", 0x7fff1231e650, 1024) = -1 EINVAL (Invalid argument) <0.000009> 7104 12:12:42.823582 stat("/sys/devices/virtual/input/input13/event13/uevent", {st_dev=makedev(0, 17), st_ino=33266, st_mode=S_IFREG|0644, st_nlink=1, st_uid=0, st_gid=0, st_blksize=4096, st_blocks=0, st_size=4 7104 12:12:42.823627 lstat("/sys/devices/virtual/input/input13/event13/name", 0x7fff1231d5d0) = -1 ENOENT (No such file or directory) <0.000009> 7104 12:12:42.823680 readlink("/sys/devices/virtual/input/mice", 0x7fff1231e650, 1024) = -1 EINVAL (Invalid argument) <0.000022> 7104 12:12:42.823714 stat("/sys/devices/virtual/input/mice/uevent", {st_dev=makedev(0, 17), st_ino=20861, st_mode=S_IFREG|0644, st_nlink=1, st_uid=0, st_gid=0, st_blksize=4096, st_blocks=0, st_size=4096, st_ati 7104 12:12:42.823743 lstat("/sys/devices/virtual/input/mice/name", 0x7fff1231d5d0) = -1 ENOENT (No such file or directory) <0.000010> 7104 12:12:42.823784 rt_sigaction(SIGSEGV, {0x400c30, [SEGV], SA_RESTORER|SA_RESTART, 0x7f4286aa9250}, {SIG_DFL, [], 0}, 8) = 0 <0.000018> 7104 12:12:42.823831 iopl(0x3) = -1 EPERM (Operation not permitted) <0.000006> 7104 12:12:42.823851 --- SIGSEGV {si_signo=SIGSEGV, si_code=SI_KERNEL, si_addr=0} --- 7104 12:12:42.823865 rt_sigreturn() = 1447909480 <0.000006> The above continues on repeatedly: 7104 12:15:06.525764 --- SIGSEGV {si_signo=SIGSEGV, si_code=SI_KERNEL, si_addr=0} --- 7104 12:15:06.525777 rt_sigreturn() = 1447909480 <0.000007> 7104 12:15:06.525797 --- SIGSEGV {si_signo=SIGSEGV, si_code=SI_KERNEL, si_addr=0} --- 7104 12:15:06.525828 rt_sigreturn() = 1447909480 <0.000006> 7104 12:15:06.525867 --- SIGINT {si_signo=SIGINT, si_code=SI_KERNEL, si_value={int=603113048, ptr=0x7f4f23f2c658}} --- 7104 12:15:06.526032 +++ killed by SIGINT +++ Version-Release number of selected component (if applicable): xorg-x11-drv-vmmouse-13.0.0-12.el7 How reproducible: Easily Steps to Reproduce: 1. Install the latest version of xorg-x11-drv-vmmouse 2. Issue a "strace /usr/bin/vmmouse_detect" 3. Observe the operation Actual results: The process endlessly encounters a SIGSEGV Expected results: Exit with 0 or 1 Additional info: If uncorrected, the issue above causes the boot process to stall for an exceptional amount of time, before systemd issues a SIGKILL to vmmouse_detect.
Looking at the end binary, it looks like the segvCB() signal handler is compiled out to a NOP. (gdb) disassemble segvCB Dump of assembler code for function segvCB: 0x0000000000400c30 <+0>: repz retq End of assembler dump. It looks like the macro below, is not defined at compile time: void segvCB(int sig) { #if defined HAVE_XORG_SERVER_1_1_0 exit(1); #endif } I'm attaching a patch to move the macro to the signal handler registration. That way, if the macro is not defined, the end result would be a death by SIGSEGV, instead of the endless loop. - Kyle Walker
Marking Regression, as the issue is not present in: xorg-x11-drv-vmmouse-13.0.0-11.el7 $ gdb ./usr/bin/vmmouse_detect (gdb) disassemble segvCB Dump of assembler code for function segvCB: 0x0000000000400670 <+0>: sub $0x8,%rsp 0x0000000000400674 <+4>: mov $0x1,%edi 0x0000000000400679 <+9>: callq 0x400530 <exit@plt> End of assembler dump. - Kyle Walker
Redacted the previous patch. The source of the failure is that in the latest update the following patch was backported: Subject: [PATCH vmmouse] Back off if we detect a vmmouse kernel driver v3 If a vmmouse kernel driver is active, vmmouse input is handled by the Xorg evdev driver and not by the vmmouse driver, so make sure the vmmouse_detect utility doesn't detect a vmmouse if a kernel driver is active. v2: Change the vmmouse kernel device name, fix comment. v3: Fix up libudev error handling. In that patch, the following is present: diff --git a/tools/vmmouse_detect.c b/tools/vmmouse_detect.c index cfb92e1..6402b16 100644 --- a/tools/vmmouse_detect.c +++ b/tools/vmmouse_detect.c @@ -30,9 +30,7 @@ #include <signal.h> #include "vmmouse_client.h" -#ifdef HAVE_CONFIG_H -#include "config.h" -#endif +extern int vmmouse_uses_kernel_driver(void); void segvCB(int sig) The above erroneously removes the "ifdef HAVE_CONFIG_H" include statement. When the above is reverted, the previous behaviour is present. Soon to append a corrected patch for the above. - Kyle Walker
Created attachment 1238054 [details] Corrected patch to include the config.h header file. Attaching patch to correct the missing config.h header file. Test build running below: build (rhel-7.3-z-test, /rpms/xorg-x11-drv-vmmouse:6b363d659e84289bc5f75e4529c4b112c34bda54) | Task Info | Brew https://brewweb.engineering.redhat.com/brew/taskinfo?taskID=12315189 Testing results: xorg-x11-drv-vmmouse-13.0.0-12.el7_3.bz1410582.x86_64.rpm $ rpm2cpio xorg-x11-drv-vmmouse-13.0.0-12.el7_3.bz1410582.x86_64.rpm | cpio -idmv ./usr/bin/vmmouse_detect ./usr/lib/udev/rules.d/69-xorg-vmmouse.rules ./usr/lib64/xorg/modules/input/vmmouse_drv.so ./usr/share/X11/xorg.conf.d/50-vmmouse.conf ./usr/share/man/man1/vmmouse_detect.1.gz ./usr/share/man/man4/vmmouse.4.gz 69 blocks $ ./usr/bin/vmmouse_detect $ echo $? 1 With the binary function disassembly: $ gdb ./usr/bin/vmmouse_detect <snip> (gdb) disassem segvCB Dump of assembler code for function segvCB: 0x0000000000400c80 <+0>: sub $0x8,%rsp 0x0000000000400c84 <+4>: mov $0x1,%edi 0x0000000000400c89 <+9>: callq 0x400b40 <exit@plt> End of assembler dump. - Kyle Walker
Rebased driver appears to have the right code in place.
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHBA-2017:1905