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author | Helge Deller <deller@gmx.de> | 2013-10-01 23:54:46 +0400 |
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committer | Helge Deller <deller@gmx.de> | 2013-10-13 19:45:20 +0400 |
commit | 59b33f148cc08fb33cbe823fca1e34f7f023765e (patch) | |
tree | 798e64224feb4399d669e5deb6fb650710b6a2d9 /arch/parisc/mm/fault.c | |
parent | a60ac4b5f0b630889a01293db52ac65003a01e98 (diff) | |
download | linux-59b33f148cc08fb33cbe823fca1e34f7f023765e.tar.xz |
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>
Diffstat (limited to 'arch/parisc/mm/fault.c')
0 files changed, 0 insertions, 0 deletions