From: Elvira Khabirova <lineprin...@altlinux.org>
Arch code should use tracehook_*() helpers, as documented
in include/linux/tracehook.h,
ptrace_report_syscall() is not expected to be used outside that file.
The patch does not look very nice, but at least it is correct
and opens the way for PTRACE_GET_SYSCALL_INFO API.
Co-authored-by: Dmitry V. Levin <l...@altlinux.org>
Fixes: 5521eb4bca2d ("powerpc/ptrace: Add support for PTRACE_SYSEMU")
Cc: Michael Ellerman <m...@ellerman.id.au>
Cc: Oleg Nesterov <o...@redhat.com>
Cc: Eugene Syromyatnikov <e...@redhat.com>
Cc: Benjamin Herrenschmidt <b...@kernel.crashing.org>
Cc: Paul Mackerras <pau...@samba.org>
Cc: Breno Leitao <lei...@debian.org>
Cc: Andy Lutomirski <l...@kernel.org>
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Elvira Khabirova <lineprin...@altlinux.org>
Signed-off-by: Dmitry V. Levin <l...@altlinux.org>
---
Notes:
v5: reverted to a simple approach, compile- and run-tested
v4: rewritten to call tracehook_report_syscall_entry() once, compile-tested
v3: add a descriptive comment
v2: explicitly ignore tracehook_report_syscall_entry() return code
arch/powerpc/kernel/ptrace.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
index afb819f4ca68..714c3480c52d 100644
--- a/arch/powerpc/kernel/ptrace.c
+++ b/arch/powerpc/kernel/ptrace.c
@@ -3266,12 +3266,17 @@ long do_syscall_trace_enter(struct pt_regs *regs)
user_exit();
if (test_thread_flag(TIF_SYSCALL_EMU)) {
- ptrace_report_syscall(regs);
/*
+ * A nonzero return code from tracehook_report_syscall_entry()
+ * tells us to prevent the syscall execution, but we are not
+ * going to execute it anyway.
+ *
* Returning -1 will skip the syscall execution. We want to
* avoid clobbering any register also, thus, not 'gotoing'
* skip label.
*/
+ if (tracehook_report_syscall_entry(regs))
+ ;
return -1;
}
--
ldv
