Messages in this thread | | | Date | Fri, 2 Jan 2015 19:05:23 +0100 | From | Oleg Nesterov <> | Subject | Re: [RFC 6/8] ARM64: Handle TRAP_HWBRKPT for user mode as well |
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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 <panand@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.
The same for the next patch.
Oleg.
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