On Tuesday, November 8, 2016 6:45:53 PM CET Eric W. Biederman wrote:
> Arnd Bergmann <arnd@xxxxxxxx> writes:
> > On Tuesday, November 8, 2016 9:16:28 AM CET Olof's autobuilder wrote:
> >> Here are the build results from automated periodic testing.
> > I think this was accidentally fixed by eedf265aa003 ("devpts: Make each mount of
> > devpts an independent filesystem."), which unfortunately is not a
> > candidate for stable
>
> Well eedf265aa003 ("devpts: Make each mount of devpts an independent
> filesystem.") does contain a somewhat serious bug fix, and it was tested
> to ensure it works everywhere so that might possibly be a canidate for
> stable.
>
> Certainly that is a change I would aim at vendor trees that care about
> containers.
>
> >> 1 net/netfilter/xt_owner.c:27:23: warning: self-comparison always evaluates to false [-Wtautological-compare]
> >
> > Apparently also fixed as a side-effect of a larger patch:
> >
> > 9847371a84b0 ("netfilter: Allow xt_owner in any user namespace")
> >
> > This one might be appropriate for a stable backport, Eric Biederman
> > would know for sure.
>
> Well it is a feature patch. This sounds like an error message that is
> only generated when user namespace support is disabled. And we are
> making it go away by making the code more expensive.
Ah, so both of these were exactly the opposite of what I expected ;-)
> I am not a great fan of that warning being on by default, as it seems to
> encourage more expensive code to be generated by macros. Has that
> warning caught any real bugs yet?
I fixed up all instanced I could find on ARM, see "git log --oneline
--grep=tautological". I'd categorize three of them as bugs:
0a938697d7fb drm/exynos: fix error handling in exynos_drm_subdrv_open
0fb504001192 [media] am437x-vfpe: fix typo in vpfe_get_app_input_index
86d65b7e7a0c nouveau: fix nv40_perfctr_next() cleanup regression
and four others as false-positive:
dd665be0e243 ARM: 8584/1: floppy: avoid gcc-6 warning
f419a08fb329 drivers/memstick/host/r592.c: avoid gcc-6 warning
e3ebd894f084 smc91x: avoid self-comparison warning
0335695dfa4d cred/userns: define current_user_ns() as a function
which is not a bad ratio at all. The last of those is probably
sufficient to address most of the gcc-6 warnings on stable-4.4.
I also did a patch to shut up four more warnings on x86, but never
got around to submitting them properly. These are all false-positive,
see patch below (I folded this into one).
Arnd
commit 28624e5166a2d33c386b6d5b7f627d84939cabce
Author: Arnd Bergmann <arnd@xxxxxxxx>
Date: Fri Oct 7 14:15:06 2016 +0200
x86: treewide: hide -Wtautological-compare warnings
proc/kcore: hide a harmless warning
fs/proc/kcore.c: In function ‘add_modules_range’:
fs/proc/kcore.c:622:161: error: self-comparison always evaluates to false [-Werror=tautological-compare]
if (/*MODULES_VADDR != VMALLOC_START && */MODULES_END != VMALLOC_END) {
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
acpi: thermal: fix gcc-6/ccache warning
drivers/acpi/processor_thermal.c: In function ‘cpufreq_set_cur_state’:
drivers/acpi/processor_thermal.c:137:36: error: self-comparison always evaluates to true [-Werror=tautological-compare]
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
x86: microcode/amd: avoid ccache/gcc-6 warning
/git/arm-soc/arch/x86/kernel/cpu/microcode/amd.c: In function ‘load_microcode_amd’:
/git/arm-soc/arch/x86/kernel/cpu/microcode/amd.c:878:30: error: self-comparison always evaluates to true [-Werror=tautological-compare]
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
sfi: avoid ccache warning
With ccache in combination with gcc-6, we get a harmless warning for the sfi subsystem,
as ccache only sees the preprocessed source:
drivers/sfi/sfi_core.c: In function ‘sfi_map_table’:
drivers/sfi/sfi_core.c:175:53: error: self-comparison always evaluates to true [-Werror=tautological-compare]
Using an inline function to do the comparison tells the compiler what is
going on even for preprocessed files, and avoids the warning.
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c
index 6f353bdb3a25..64a457da4a4c 100644
--- a/arch/x86/kernel/cpu/microcode/amd.c
+++ b/arch/x86/kernel/cpu/microcode/amd.c
@@ -854,6 +854,7 @@ static enum ucode_state
load_microcode_amd(int cpu, u8 family, const u8 *data, size_t size)
{
enum ucode_state ret;
+ int bootcpu = boot_cpu_data.cpu_index;
/* free old equiv table */
free_equiv_cpu_table();
@@ -865,7 +866,7 @@ load_microcode_amd(int cpu, u8 family, const u8 *data, size_t size)
#ifdef CONFIG_X86_32
/* save BSP's matching patch for early load */
- if (cpu_data(cpu).cpu_index == boot_cpu_data.cpu_index) {
+ if (cpu_data(cpu).cpu_index == bootcpu) {
struct ucode_patch *p = find_patch(cpu);
if (p) {
memset(amd_ucode_patch, 0, PATCH_MAX_SIZE);
diff --git a/drivers/acpi/processor_thermal.c b/drivers/acpi/processor_thermal.c
index 1fed84a092c2..8cde6715537b 100644
--- a/drivers/acpi/processor_thermal.c
+++ b/drivers/acpi/processor_thermal.c
@@ -122,20 +122,22 @@ static int cpufreq_get_cur_state(unsigned int cpu)
static int cpufreq_set_cur_state(unsigned int cpu, int state)
{
int i;
+ int id;
if (!cpu_has_cpufreq(cpu))
return 0;
reduction_pctg(cpu) = state;
+ id = topology_physical_package_id(cpu);
+
/*
* Update all the CPUs in the same package because they all
* contribute to the temperature and often share the same
* frequency.
*/
for_each_online_cpu(i) {
- if (topology_physical_package_id(i) ==
- topology_physical_package_id(cpu))
+ if (topology_physical_package_id(i) == id)
cpufreq_update_policy(i);
}
return 0;
diff --git a/drivers/sfi/sfi_core.c b/drivers/sfi/sfi_core.c
index 296db7a69c27..a8f2313a2613 100644
--- a/drivers/sfi/sfi_core.c
+++ b/drivers/sfi/sfi_core.c
@@ -71,9 +71,12 @@
#include "sfi_core.h"
-#define ON_SAME_PAGE(addr1, addr2) \
- (((unsigned long)(addr1) & PAGE_MASK) == \
- ((unsigned long)(addr2) & PAGE_MASK))
+static inline bool on_same_page(unsigned long addr1, unsigned long addr2)
+{
+ return (addr1 & PAGE_MASK) == (addr2 & PAGE_MASK);
+}
+
+#define ON_SAME_PAGE(addr1, addr2) on_same_page((unsigned long)addr1, (unsigned long)addr2)
#define TABLE_ON_PAGE(page, table, size) (ON_SAME_PAGE(page, table) && \
ON_SAME_PAGE(page, table + size))
diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c
index 5c89a07e3d7f..8ca8de0d13eb 100644
--- a/fs/proc/kcore.c
+++ b/fs/proc/kcore.c
@@ -616,12 +616,14 @@ static void __init proc_kcore_text_init(void)
/*
* MODULES_VADDR has no intersection with VMALLOC_ADDR.
*/
-struct kcore_list kcore_modules;
+static struct kcore_list kcore_modules;
static void __init add_modules_range(void)
{
- if (MODULES_VADDR != VMALLOC_START && MODULES_END != VMALLOC_END) {
- kclist_add(&kcore_modules, (void *)MODULES_VADDR,
- MODULES_END - MODULES_VADDR, KCORE_VMALLOC);
+ void *start = (void *)MODULES_VADDR;
+ size_t len = MODULES_END - MODULES_VADDR;
+
+ if (start != (void *)VMALLOC_START && len != VMALLOC_END - VMALLOC_START) {
+ kclist_add(&kcore_modules, start, len, KCORE_VMALLOC);
}
}
#else
--
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