3.16.7-ckt24 -stable review patch. If anyone has any objections, please let me know.
---8<------------------------------------------------------------ From: John Blackwood <john.blackw...@ccur.com> commit 5db4fd8c52810bd9740c1240ebf89223b171aa70 upstream. Make sure to clear out any ptrace singlestep state when a ptrace(2) PTRACE_DETACH call is made on arm64 systems. Otherwise, the previously ptraced task will die off with a SIGTRAP signal if the debugger just previously singlestepped the ptraced task. Signed-off-by: John Blackwood <john.blackw...@ccur.com> [will: added comment to justify why this is in the arch code] Signed-off-by: Will Deacon <will.dea...@arm.com> Signed-off-by: Luis Henriques <luis.henriq...@canonical.com> --- arch/arm64/kernel/ptrace.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index 167c5edecad4..d2b9a3f7457d 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -55,6 +55,12 @@ */ void ptrace_disable(struct task_struct *child) { + /* + * This would be better off in core code, but PTRACE_DETACH has + * grown its fair share of arch-specific worts and changing it + * is likely to cause regressions on obscure architectures. + */ + user_disable_single_step(child); } #ifdef CONFIG_HAVE_HW_BREAKPOINT