[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v2 0/2] kexec: Use hypercall_create_continuation to protect KEXEC ops
During testing (using the script below) we found that multiple invocations of kexec of unload/load are not safe. This does not exist in classic Xen kernels in which the kexec-tools did the kexec via Linux kernel syscall (which in turn made the hypercall), as the Linux code has a mutex_trylock which would inhibit multiple concurrent calls. But with the kexec-tools utilizing xc_kexec_* that is no longer the case and we need to protect against multiple concurrent invocations. Please see the patches and review at your convenience! ==== try-crash.pl from bhavesh.davda@xxxxxxxxxx ==== #!/usr/bin/perl -w use strict; use warnings; use threads; sub threaded_task { threads->create(sub { my $thr_id = threads->self->tid; #print "Starting load thread $thr_id\n"; system("/sbin/kexec -p --command-line=\"placeholder root=/dev/mapper/nimbula-root ro rhbg console=tty0 console=hvc0 earlyprintk=xen nomodeset printk.time=1 irqpoll maxcpus=1 nr_cpus=1 reset_devices cgroup_disable=memory mce=off selinux=0 console=ttyS1,115200n8\" --initrd=/boot/initrd-4.1.12-61.1.9.el6uek.x86_64kdump.img /boot/vmlinuz-4.1.12-61.1.9.el6uek.x86_64"); #print "Ending load thread $thr_id\n"; threads->detach(); #End thread. }); threads->create(sub { my $thr_id = threads->self->tid; #print "Starting unload thread $thr_id\n"; system("/sbin/kexec -p -u"); #print "Ending unload thread $thr_id\n"; threads->detach(); #End thread. }); } for my $i (0..99) { threaded_task(); } Eric DeVolder (2): kexec: use hypercall_create_continuation to protect KEXEC ops kexec: remove spinlock now that all KEXEC hypercall ops are protected at the top-level xen/common/kexec.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) -- 2.7.4 _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx https://lists.xen.org/xen-devel
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