linux/arch/parisc
Helge Deller 59b33f148c parisc: fix interruption handler to respect pagefault_disable()
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>
Cc: <stable@vger.kernel.org> # v3.0+
Signed-off-by: John David Anglin  <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>
2013-10-13 17:45:20 +02:00
..
configs parisc: add defconfig for c8000 machine 2013-07-31 23:42:10 +02:00
hpux [readdir] constify ->actor 2013-06-29 12:57:05 +04:00
include parisc: mark parisc_terminate() noreturn and cold. 2013-10-13 17:44:49 +02:00
kernel parisc: fix interruption handler to respect pagefault_disable() 2013-10-13 17:45:20 +02:00
lib parisc: Fix gcc miscompilation in pa_memcpy() 2013-07-09 22:09:23 +02:00
math-emu parisc: avoid undefined shift in cnv_float.h 2013-01-07 23:06:22 +01:00
mm arch/parisc/mm/fault.c: fix uninitialized variable usage 2013-09-30 14:31:02 -07:00
oprofile oprofile: more whitespace fixes 2008-10-15 20:55:51 +02:00
defpalo.conf parisc: switch to gzip-compressed vmlinuz kernel 2013-07-09 22:09:20 +02:00
install.sh parisc: switch to gzip-compressed vmlinuz kernel 2013-07-09 22:09:20 +02:00
Kconfig Remove GENERIC_HARDIRQ config option 2013-09-13 15:09:52 +02:00
Kconfig.debug consolidate per-arch stack overflow debugging options 2013-07-04 11:25:39 -07:00
Makefile parisc: switch to gzip-compressed vmlinuz kernel 2013-07-09 22:09:20 +02:00
nm