On Mon, Aug 24, 2015 at 5:19 PM, Stephen Boyd <sb...@codeaurora.org> wrote: > On 08/24/2015 04:58 PM, Douglas Anderson wrote: >> >> If we're in kgdb then the machine is already stopped. Trying to stop >> it again will cause us to try to sleep, which is not allowed while in >> kgdb. To avoid this problem, only stop the machine when we're not in >> kgdb. >> >> Reported-by: Aapo Vienamo <avien...@nvidia.com> >> Suggested-by: Kees Cook <keesc...@chromium.org>
I actually suggested using in_atomic_preempt_off() which is I think a better catch-all. Could you use that instead, please? -Kees >> Signed-off-by: Douglas Anderson <diand...@chromium.org> >> --- > > > Can you add the backtrace? > >> arch/arm/kernel/patch.c | 7 ++++++- >> 1 file changed, 6 insertions(+), 1 deletion(-) >> >> diff --git a/arch/arm/kernel/patch.c b/arch/arm/kernel/patch.c >> index 69bda1a..abf30ec 100644 >> --- a/arch/arm/kernel/patch.c >> +++ b/arch/arm/kernel/patch.c >> @@ -1,5 +1,6 @@ >> #include <linux/kernel.h> >> #include <linux/spinlock.h> >> +#include <linux/kgdb.h> >> #include <linux/kprobes.h> >> #include <linux/mm.h> >> #include <linux/stop_machine.h> >> @@ -124,6 +125,9 @@ void __kprobes patch_text(void *addr, unsigned int >> insn) >> .insn = insn, >> }; >> - stop_machine(patch_text_stop_machine, &patch, NULL); >> + /* Stop machine before patching; but not if in the debugger */ >> + if (unlikely(in_dbg_master())) >> + patch_text_stop_machine(&patch); >> + else >> + stop_machine(patch_text_stop_machine, &patch, NULL); >> } > > > Perhaps it would be better to add a different function for the kgdb call > site? Then it's explicit what's going on without us having to figure out > when in_dbg_master() is true. > > -- > Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, > a Linux Foundation Collaborative Project > -- Kees Cook Chrome OS Security -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/