Messages in this thread | | | Date | Wed, 14 Nov 2018 14:57:18 -0800 | From | Matthias Kaehlcke <> | Subject | Re: [PATCH v2] sysrq: Use panic() to force a crash |
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On Thu, Sep 20, 2018 at 10:12:53AM -0700, Matthias Kaehlcke wrote: > sysrq_handle_crash() currently forces a crash by dereferencing a > NULL pointer, which is undefined behavior in C. Just call panic() > instead, which is simpler and doesn't depend on compiler specific > handling of the undefined behavior. > > Remove the comment on why the RCU lock needs to be released, it isn't > accurate anymore since the crash now isn't handled by the page fault > handler (for reference: the comment was added by commit 984cf355aeaa > ("sysrq: Fix warning in sysrq generated crash.")). Releasing the lock > is still good practice though. > > Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > Signed-off-by: Matthias Kaehlcke <mka@chromium.org> > --- > drivers/tty/sysrq.c | 13 +++---------- > 1 file changed, 3 insertions(+), 10 deletions(-) > > diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c > index 06ed20dd01ba..d779a51499a0 100644 > --- a/drivers/tty/sysrq.c > +++ b/drivers/tty/sysrq.c > @@ -134,17 +134,10 @@ static struct sysrq_key_op sysrq_unraw_op = { > > static void sysrq_handle_crash(int key) > { > - char *killer = NULL; > - > - /* we need to release the RCU read lock here, > - * otherwise we get an annoying > - * 'BUG: sleeping function called from invalid context' > - * complaint from the kernel before the panic. > - */ > + /* release the RCU read lock before crashing */ > rcu_read_unlock(); > - panic_on_oops = 1; /* force panic */ > - wmb(); > - *killer = 1; > + > + panic("sysrq triggered crash\n"); > } > static struct sysrq_key_op sysrq_crash_op = { > .handler = sysrq_handle_crash,
Does this need further changes or is it ready to land?
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