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authorHelge Deller <deller@gmx.de>2013-10-01 23:54:46 +0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-10-22 11:41:44 +0400
commitac008905d50badfe8b695fa3f1eef20ac352e3e6 (patch)
treebb51be0f6e7992abf9eea1c67f0789c4fcef52be /drivers/watchdog/ts72xx_wdt.c
parent546a50594e6241e2002cddbef7c350e177e08e52 (diff)
downloadlinux-sunxi-ac008905d50badfe8b695fa3f1eef20ac352e3e6.tar.xz
parisc: fix interruption handler to respect pagefault_disable()
commit 59b33f148cc08fb33cbe823fca1e34f7f023765e upstream. Running an "echo t > /proc/sysrq-trigger" crashes the parisc kernel. The problem is, that in print_worker_info() we try to read the workqueue info via the probe_kernel_read() functions which use pagefault_disable() to avoid crashes like this: probe_kernel_read(&pwq, &worker->current_pwq, sizeof(pwq)); probe_kernel_read(&wq, &pwq->wq, sizeof(wq)); probe_kernel_read(name, wq->name, sizeof(name) - 1); The problem here is, that the first probe_kernel_read(&pwq) might return zero in pwq and as such the following probe_kernel_reads() try to access contents of the page zero which is read protected and generate a kernel segfault. With this patch we fix the interruption handler to call parisc_terminate() directly only if pagefault_disable() was not called (in which case preempt_count()==0). Otherwise we hand over to the pagefault handler which will try to look up the faulting address in the fixup tables. Signed-off-by: Helge Deller <deller@gmx.de> Signed-off-by: John David Anglin <dave.anglin@bell.net> Signed-off-by: Helge Deller <deller@gmx.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/watchdog/ts72xx_wdt.c')
0 files changed, 0 insertions, 0 deletions