Re: [v2][PATCH 3/3] powerpc/kgdb: restore current_thread_infoproperly

From: Nicholas A. Bellinger
Date: Wed Aug 22 2012 - 23:14:20 EST


On Thu, 2012-08-23 at 10:10 +0800, Tiejun Chen wrote:
> For powerpc BooKE and e200, singlestep is handled on the critical/dbg
> exception stack. This causes current_thread_info() to fail for kgdb
> internal, so previously We work around this issue by copying
> the thread_info from the kernel stack before calling kgdb_handle_exception,
> and copying it back afterwards.
>
> But actually we don't do this properly. We should backup current_thread_info
> then restore that when exit.
>
> Signed-off-by: Tiejun Chen <tiejun.chen@xxxxxxxxxxxxx>
> ---
> v2: fix a typo in patch head description.
>
> arch/powerpc/kernel/kgdb.c | 11 +++++++++--
> 1 files changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/arch/powerpc/kernel/kgdb.c b/arch/powerpc/kernel/kgdb.c
> index 05adb69..c470a40 100644
> --- a/arch/powerpc/kernel/kgdb.c
> +++ b/arch/powerpc/kernel/kgdb.c
> @@ -25,6 +25,7 @@
> #include <asm/processor.h>
> #include <asm/machdep.h>
> #include <asm/debug.h>
> +#include <linux/slab.h>
>
> /*
> * This table contains the mapping between PowerPC hardware trap types, and
> @@ -153,6 +154,8 @@ static int kgdb_handle_breakpoint(struct pt_regs *regs)
> static int kgdb_singlestep(struct pt_regs *regs)
> {
> struct thread_info *thread_info, *exception_thread_info;
> + struct thread_info *backup_current_thread_info = \
> + (struct thread_info *)kmalloc(sizeof(struct thread_info), GFP_KERNEL);
>

Looks like a rouge '\' in the above assignment..


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