On Tuesday, November 8, 2016 6:45:53 PM CET Eric W. Biederman wrote:
Arnd Bergmann arnd@arndb.de 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@arndb.de 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@arndb.de
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@arndb.de
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@arndb.de
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@arndb.de
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