On Thursday 08 January 2015 10:31 PM, Will Deacon wrote:
On Fri, Jan 02, 2015 at 06:05:23PM +0000, Oleg Nesterov wrote:
Let me repeat once again that I know absolutely nothing about arm* ;)
On 12/31, Pratyush Anand wrote:
uprobe registers a handler at step_hook. So, single_step_handler now
checks for user mode as well if there is a valid hook.
Signed-off-by: Pratyush Anand <pan...@redhat.com>
---
arch/arm64/kernel/debug-monitors.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/arm64/kernel/debug-monitors.c
b/arch/arm64/kernel/debug-monitors.c
index b056369fd47d..2676b8655241 100644
--- a/arch/arm64/kernel/debug-monitors.c
+++ b/arch/arm64/kernel/debug-monitors.c
@@ -236,6 +236,9 @@ static int single_step_handler(unsigned long addr, unsigned
int esr,
if (!reinstall_suspended_bps(regs))
return 0;
+ if (call_step_hook(regs, esr) == DBG_HOOK_HANDLED)
+ return 0;
+
if (user_mode(regs)) {
info.si_signo = SIGTRAP;
info.si_errno = 0;
@@ -251,9 +254,6 @@ static int single_step_handler(unsigned long addr, unsigned
int esr,
*/
user_rewind_single_step(current);
} else {
- if (call_step_hook(regs, esr) == DBG_HOOK_HANDLED)
- return 0;
-
Agreed, we need something like this change...
But did you verify that it can't break other users of register_step_hook() ?
The current handlers do not check user_mode() == F, they assume that they
can't be called otherwise.
If this all is correct, please explain why in the changelog.
I think you're right, and kgdb will need fixing with this change.
OK, I will fix kgdb too when I will send next revision.
~Pratyush
Will
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