[PATCH v2 1/3] powerpc: Don't force ENOSYS as error on syscall fail
From: Bogdan Purcareata <hidden>
Date: 2015-02-11 08:36:33
Also in:
lkml
Subsystem:
linux for powerpc (32-bit and 64-bit), ptrace support, the rest · Maintainers:
Madhavan Srinivasan, Oleg Nesterov, Linus Torvalds
In certain scenarios - e.g. seccomp filtering with ERRNO as default action - the system call fails for other reasons than the syscall not being available. The seccomp filter can be configured to store a user-defined error code on return from a blacklisted syscall. Don't always set ENOSYS on do_syscall_trace_enter failure. v2: - move setting ENOSYS as errno from the syscall entry assembly to do_syscall_trace_enter, only in the specific case Signed-off-by: Bogdan Purcareata <redacted> --- arch/powerpc/kernel/entry_32.S | 2 +- arch/powerpc/kernel/entry_64.S | 1 - arch/powerpc/kernel/ptrace.c | 4 +++- 3 files changed, 4 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index 10a0935..d2c58a3 100644
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S@@ -425,7 +425,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_NEED_PAIRED_STWCX) b 1b #endif /* CONFIG_44x */ -66: li r3,-ENOSYS +66: b ret_from_syscall .globl ret_from_fork
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index 194e46d..0111e04 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S@@ -269,7 +269,6 @@ syscall_dotrace: b .Lsyscall_dotrace_cont syscall_enosys: - li r3,-ENOSYS b syscall_exit syscall_exit_work:
diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
index f21897b..d82fd0b 100644
--- a/arch/powerpc/kernel/ptrace.c
+++ b/arch/powerpc/kernel/ptrace.c@@ -1775,13 +1775,15 @@ long do_syscall_trace_enter(struct pt_regs *regs) secure_computing_strict(regs->gpr[0]); if (test_thread_flag(TIF_SYSCALL_TRACE) && - tracehook_report_syscall_entry(regs)) + tracehook_report_syscall_entry(regs)) { /* * Tracing decided this syscall should not happen. * We'll return a bogus call number to get an ENOSYS * error, but leave the original number in regs->gpr[0]. */ ret = -1L; + syscall_set_return_value(current, regs, -ENOSYS, 0); + } if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT))) trace_sys_enter(regs, regs->gpr[0]);
--
2.1.4