On Fri, Jan 22, 2021 at 03:08:31PM +0530, Sumit Garg wrote: > Currently kdb uses in_interrupt() to determine whether it's library > code has been called from the kgdb trap handler or from a saner calling > context such as driver init. This approach is broken because > in_interrupt() alone isn't able to determine kgdb trap handler entry via > normal task context such as [1]. > > We can improve this by adding check for in_dbg_master() which explicitly > determines if we are running in debugger context. Also, use in_atomic() > instead of in_interrupt() as the former is more appropriate to know atomic > context and moreover the later one is deprecated.
Why do we need the in_atomic() here? Or put another way, why isn't in_dbg_master() sufficient? Daniel. > > [1] $ echo g > /proc/sysrq-trigger > > Signed-off-by: Sumit Garg <sumit.g...@linaro.org> > --- > kernel/debug/kdb/kdb_private.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/debug/kdb/kdb_private.h b/kernel/debug/kdb/kdb_private.h > index 7a4a181..7a9ebd9 100644 > --- a/kernel/debug/kdb/kdb_private.h > +++ b/kernel/debug/kdb/kdb_private.h > @@ -231,7 +231,7 @@ extern struct task_struct *kdb_curr_task(int); > > #define kdb_task_has_cpu(p) (task_curr(p)) > > -#define GFP_KDB (in_interrupt() ? GFP_ATOMIC : GFP_KERNEL) > +#define GFP_KDB (in_atomic() || in_dbg_master() ? GFP_ATOMIC : GFP_KERNEL) > > extern void *debug_kmalloc(size_t size, gfp_t flags); > extern void debug_kfree(void *); > -- > 2.7.4 >
