On Mon, Apr 16, 2012 at 10:32 AM, Will Drewry <wad@xxxxxxxxxxxx> wrote:
> On Mon, Apr 16, 2012 at 12:46 AM, Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> wrote:
>> Hi all,
>>
>> After merging the final tree, today's linux-next build (powerpc
>> allnoconfig) failed like this:
>>
>> arch/powerpc/kernel/ptrace.c: In function 'do_syscall_trace_enter':
>> arch/powerpc/kernel/ptrace.c:1713:2: error: statement with no effect [-Werror=unused-value]
>> cc1: all warnings being treated as errors
>>
>> Introduced by commit acf3b2c71ed2 ("seccomp: add SECCOMP_RET_ERRNO"). I
>> have applied the following hack fix that fixes the build, but the other
>> seven call sites of secure_computing() should be fixed up properly.
>
> Thanks for this, and the other two fixes! I'll pull together a patch
> fixing up the other call sites.
Hrm - with liberal application of grep and lxr, I'm not seeing any
other call sites that need to be fixed. I ended up with the exact
same patch as yours.
At present, the return value from secure_computing() can be ignored
for every arch that supports CONFIG_SECCOMP and does not support
CONFIG_HAVE_ARCH_SECCOMP_FILTER, so I don't necessarily see your patch
as a hack. Then as the pieces needed to support
CONFIG_HAVE_ARCH_SECCOMP_FILTER end up in place, the (void) cast will
be removed. (Respecting the return value is noted in the arch/Kconfig
description for adding support.)
I certainly don't mind bouncing the casts patch (broken out per-arch)
over to James's tree so that you don't have to carry the fix, but I
wonder if I'm missing some implicit context.
Thanks!
will
>
>> From: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
>> Date: Mon, 16 Apr 2012 15:39:49 +1000
>> Subject: [PATCH] seccomp: hack fix for build failures with secure_computing
>> return value change
>>
>> Signed-off-by: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
>> ---
>> arch/microblaze/kernel/ptrace.c | 2 +-
>> arch/mips/kernel/ptrace.c | 2 +-
>> arch/powerpc/kernel/ptrace.c | 2 +-
>> arch/s390/kernel/ptrace.c | 2 +-
>> arch/sh/kernel/ptrace_32.c | 2 +-
>> arch/sh/kernel/ptrace_64.c | 2 +-
>> arch/sparc/kernel/ptrace_64.c | 2 +-
>> 7 files changed, 7 insertions(+), 7 deletions(-)
>>
>> diff --git a/arch/microblaze/kernel/ptrace.c b/arch/microblaze/kernel/ptrace.c
>> index 6eb2aa9..9e3ffc9 100644
>> --- a/arch/microblaze/kernel/ptrace.c
>> +++ b/arch/microblaze/kernel/ptrace.c
>> @@ -136,7 +136,7 @@ asmlinkage long do_syscall_trace_enter(struct pt_regs *regs)
>> {
>> long ret = 0;
>>
>> - secure_computing(regs->r12);
>> + (void)secure_computing(regs->r12);
>>
>> if (test_thread_flag(TIF_SYSCALL_TRACE) &&
>> tracehook_report_syscall_entry(regs))
>> diff --git a/arch/mips/kernel/ptrace.c b/arch/mips/kernel/ptrace.c
>> index 7c24c29..4f83d73 100644
>> --- a/arch/mips/kernel/ptrace.c
>> +++ b/arch/mips/kernel/ptrace.c
>> @@ -535,7 +535,7 @@ static inline int audit_arch(void)
>> asmlinkage void syscall_trace_enter(struct pt_regs *regs)
>> {
>> /* do the secure computing check first */
>> - secure_computing(regs->regs[2]);
>> + (void)secure_computing(regs->regs[2]);
>>
>> if (!(current->ptrace & PT_PTRACED))
>> goto out;
>> diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
>> index 8d8e028..53cebc4 100644
>> --- a/arch/powerpc/kernel/ptrace.c
>> +++ b/arch/powerpc/kernel/ptrace.c
>> @@ -1710,7 +1710,7 @@ long do_syscall_trace_enter(struct pt_regs *regs)
>> {
>> long ret = 0;
>>
>> - secure_computing(regs->gpr[0]);
>> + (void)secure_computing(regs->gpr[0]);
>>
>> if (test_thread_flag(TIF_SYSCALL_TRACE) &&
>> tracehook_report_syscall_entry(regs))
>> diff --git a/arch/s390/kernel/ptrace.c b/arch/s390/kernel/ptrace.c
>> index 02f300f..96e0dea 100644
>> --- a/arch/s390/kernel/ptrace.c
>> +++ b/arch/s390/kernel/ptrace.c
>> @@ -719,7 +719,7 @@ asmlinkage long do_syscall_trace_enter(struct pt_regs *regs)
>> long ret = 0;
>>
>> /* Do the secure computing check first. */
>> - secure_computing(regs->gprs[2]);
>> + (void)secure_computing(regs->gprs[2]);
>>
>> /*
>> * The sysc_tracesys code in entry.S stored the system
>> diff --git a/arch/sh/kernel/ptrace_32.c b/arch/sh/kernel/ptrace_32.c
>> index 9698671..cf55945 100644
>> --- a/arch/sh/kernel/ptrace_32.c
>> +++ b/arch/sh/kernel/ptrace_32.c
>> @@ -503,7 +503,7 @@ asmlinkage long do_syscall_trace_enter(struct pt_regs *regs)
>> {
>> long ret = 0;
>>
>> - secure_computing(regs->regs[0]);
>> + (void)secure_computing(regs->regs[0]);
>>
>> if (test_thread_flag(TIF_SYSCALL_TRACE) &&
>> tracehook_report_syscall_entry(regs))
>> diff --git a/arch/sh/kernel/ptrace_64.c b/arch/sh/kernel/ptrace_64.c
>> index bc81e07..3d3600f 100644
>> --- a/arch/sh/kernel/ptrace_64.c
>> +++ b/arch/sh/kernel/ptrace_64.c
>> @@ -522,7 +522,7 @@ asmlinkage long long do_syscall_trace_enter(struct pt_regs *regs)
>> {
>> long long ret = 0;
>>
>> - secure_computing(regs->regs[9]);
>> + (void)secure_computing(regs->regs[9]);
>>
>> if (test_thread_flag(TIF_SYSCALL_TRACE) &&
>> tracehook_report_syscall_entry(regs))
>> diff --git a/arch/sparc/kernel/ptrace_64.c b/arch/sparc/kernel/ptrace_64.c
>> index 6f97c07..6ddec1f 100644
>> --- a/arch/sparc/kernel/ptrace_64.c
>> +++ b/arch/sparc/kernel/ptrace_64.c
>> @@ -1062,7 +1062,7 @@ asmlinkage int syscall_trace_enter(struct pt_regs *regs)
>> int ret = 0;
>>
>> /* do the secure computing check first */
>> - secure_computing(regs->u_regs[UREG_G1]);
>> + (void)secure_computing(regs->u_regs[UREG_G1]);
>>
>> if (test_thread_flag(TIF_SYSCALL_TRACE))
>> ret = tracehook_report_syscall_entry(regs);
>> --
>> 1.7.10.rc3
>>
>> --
>> Cheers,
>> Stephen Rothwell sfr@xxxxxxxxxxxxxxxx
>> http://www.canb.auug.org.au/~sfr/
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