Merge branch 'maybe-uninitialized' (patches from Arnd)

Merge fixes for -Wmaybe-uninitialized from Arnd Bergmann:
 "It took a while for some patches to make it into mainline through
  maintainer trees, but the 28-patch series is now reduced to 10, with
  one tiny patch added at the end.

  Aside from patches that are no longer required, I did these changes
  compared to version 1:

   - Dropped "iio: maxim_thermocouple: detect invalid storage size in
     read()", which is currently in linux-next as commit 32cb7d27e65d.
     This is the only remaining warning I see for a couple of corner
     cases (kbuild bot reports it on blackfin, kernelci bot and arm-soc
     bot both report it on arm64)

   - Dropped "brcmfmac: avoid maybe-uninitialized warning in
     brcmf_cfg80211_start_ap", which is currently in net/master merge
     pending.

   - Dropped two x86 patches, "x86: math-emu: possible uninitialized
     variable use" and "x86: mark target address as output in 'insb'
     asm" as they do not seem to trigger for a default build, and I got
     no feedback on them. Both of these are ancient issues and seem
     harmless, I will send them again to the x86 maintainers once the
     rest is merged.

   - Dropped "rbd: false-postive gcc-4.9 -Wmaybe-uninitialized" based on
     feedback from Ilya Dryomov, who already has a different fix queued
     up for v4.10. The kbuild bot reports this as a warning for xtensa.

   - Replaced "crypto: aesni: avoid -Wmaybe-uninitialized warning" with
     a simpler patch, this one always triggers but my first solution
     would not be safe for linux-4.9 any more at this point. I'll follow
     up with the larger patch as a cleanup for 4.10.

   - Replaced "dib0700: fix nec repeat handling" with a better one,
     contributed by Sean Young"

* -Wmaybe-uninitialized fixes:
  Kbuild: enable -Wmaybe-uninitialized warnings by default
  pcmcia: fix return value of soc_pcmcia_regulator_set
  infiniband: shut up a maybe-uninitialized warning
  crypto: aesni: shut up -Wmaybe-uninitialized warning
  rc: print correct variable for z8f0811
  dib0700: fix nec repeat handling
  s390: pci: don't print uninitialized data for debugging
  nios2: fix timer initcall return value
  x86: apm: avoid uninitialized data
  NFSv4.1: work around -Wmaybe-uninitialized warning
  Kbuild: enable -Wmaybe-uninitialized warning for "make W=1"

12 files changed, 55 insertions, 39 deletions

diff --git a/Makefile b/Makefile
index f97f786de58d..06e2b73978e8 100644
--- a/Makefile
+++ b/Makefile
@@ -370,7 +370,7 @@ LDFLAGS_MODULE  =
 CFLAGS_KERNEL   =
 AFLAGS_KERNEL   =
 LDFLAGS_vmlinux =
-CFLAGS_GCOV     = -fprofile-arcs -ftest-coverage -fno-tree-loop-im
+CFLAGS_GCOV     = -fprofile-arcs -ftest-coverage -fno-tree-loop-im -Wno-maybe-uninitialized
 CFLAGS_KCOV     := $(call cc-option,-fsanitize-coverage=trace-pc,)
 
 
@@ -620,7 +620,6 @@ ARCH_CFLAGS :=
 include arch/$(SRCARCH)/Makefile
 
 KBUILD_CFLAGS   += $(call cc-option,-fno-delete-null-pointer-checks,)
-KBUILD_CFLAGS   += $(call cc-disable-warning,maybe-uninitialized,)
 KBUILD_CFLAGS   += $(call cc-disable-warning,frame-address,)
 
 ifdef CONFIG_LD_DEAD_CODE_DATA_ELIMINATION
@@ -629,15 +628,18 @@ KBUILD_CFLAGS	+= $(call cc-option,-fdata-sections,)
 endif
 
 ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE
-KBUILD_CFLAGS   += -Os
+KBUILD_CFLAGS   += -Os $(call cc-disable-warning,maybe-uninitialized,)
 else
 ifdef CONFIG_PROFILE_ALL_BRANCHES
-KBUILD_CFLAGS   += -O2
+KBUILD_CFLAGS   += -O2 $(call cc-disable-warning,maybe-uninitialized,)
 else
 KBUILD_CFLAGS   += -O2
 endif
 endif
 
+KBUILD_CFLAGS += $(call cc-ifversion, -lt, 0409, \
+                        $(call cc-disable-warning,maybe-uninitialized,))
+
 # Tell gcc to never replace conditional load with a non-conditional one
 KBUILD_CFLAGS   += $(call cc-option,--param=allow-store-data-races=0)
 
diff --git a/arch/arc/Makefile b/arch/arc/Makefile
index 864adad52280..25f81a1db9f9 100644
--- a/arch/arc/Makefile
+++ b/arch/arc/Makefile
@@ -68,7 +68,9 @@ cflags-$(CONFIG_ARC_DW2_UNWIND)		+= -fasynchronous-unwind-tables $(cfi)
 ifndef CONFIG_CC_OPTIMIZE_FOR_SIZE
 # Generic build system uses -O2, we want -O3
 # Note: No need to add to cflags-y as that happens anyways
-ARCH_CFLAGS += -O3
+#
+# Disable the false maybe-uninitialized warings gcc spits out at -O3
+ARCH_CFLAGS += -O3 $(call cc-disable-warning,maybe-uninitialized,)
 endif
 
 # small data is default for elf32 tool-chain. If not usable, disable it
diff --git a/arch/nios2/kernel/time.c b/arch/nios2/kernel/time.c
index d9563ddb337e..746bf5caaffc 100644
--- a/arch/nios2/kernel/time.c
+++ b/arch/nios2/kernel/time.c
@@ -324,6 +324,7 @@ static int __init nios2_time_init(struct device_node *timer)
                 ret = nios2_clocksource_init(timer);
                 break;
         default:
+                ret = 0;
                 break;
         }
 
diff --git a/arch/s390/pci/pci_dma.c b/arch/s390/pci/pci_dma.c
index 7350c8bc13a2..6b2f72f523b9 100644
--- a/arch/s390/pci/pci_dma.c
+++ b/arch/s390/pci/pci_dma.c
@@ -423,7 +423,7 @@ static int __s390_dma_map_sg(struct device *dev, struct scatterlist *sg,
         dma_addr_t dma_addr_base, dma_addr;
         int flags = ZPCI_PTE_VALID;
         struct scatterlist *s;
-        unsigned long pa;
+        unsigned long pa = 0;
         int ret;
 
         size = PAGE_ALIGN(size);
diff --git a/arch/x86/crypto/aesni-intel_glue.c b/arch/x86/crypto/aesni-intel_glue.c
index 0ab5ee1c26af..aa8b0672f87a 100644
--- a/arch/x86/crypto/aesni-intel_glue.c
+++ b/arch/x86/crypto/aesni-intel_glue.c
@@ -888,7 +888,7 @@ static int helper_rfc4106_encrypt(struct aead_request *req)
         unsigned long auth_tag_len = crypto_aead_authsize(tfm);
         u8 iv[16] __attribute__ ((__aligned__(AESNI_ALIGN)));
         struct scatter_walk src_sg_walk;
-        struct scatter_walk dst_sg_walk;
+        struct scatter_walk dst_sg_walk = {};
         unsigned int i;
 
         /* Assuming we are supporting rfc4106 64-bit extended */
@@ -968,7 +968,7 @@ static int helper_rfc4106_decrypt(struct aead_request *req)
         u8 iv[16] __attribute__ ((__aligned__(AESNI_ALIGN)));
         u8 authTag[16];
         struct scatter_walk src_sg_walk;
-        struct scatter_walk dst_sg_walk;
+        struct scatter_walk dst_sg_walk = {};
         unsigned int i;
 
         if (unlikely(req->assoclen != 16 && req->assoclen != 20))
diff --git a/arch/x86/kernel/apm_32.c b/arch/x86/kernel/apm_32.c
index c7364bd633e1..51287cd90bf6 100644
--- a/arch/x86/kernel/apm_32.c
+++ b/arch/x86/kernel/apm_32.c
@@ -1042,8 +1042,11 @@ static int apm_get_power_status(u_short *status, u_short *bat, u_short *life)
 
         if (apm_info.get_power_status_broken)
                 return APM_32_UNSUPPORTED;
-        if (apm_bios_call(&call))
+        if (apm_bios_call(&call)) {
+                if (!call.err)
+                        return APM_NO_ERROR;
                 return call.err;
+        }
         *status = call.ebx;
         *bat = call.ecx;
         if (apm_info.get_power_status_swabinminutes) {
diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c
index 36bf50ebb187..89a6b0546804 100644
--- a/drivers/infiniband/core/cma.c
+++ b/drivers/infiniband/core/cma.c
@@ -1094,47 +1094,47 @@ static void cma_save_ib_info(struct sockaddr *src_addr,
         }
 }
 
-static void cma_save_ip4_info(struct sockaddr *src_addr,
-                              struct sockaddr *dst_addr,
+static void cma_save_ip4_info(struct sockaddr_in *src_addr,
+                              struct sockaddr_in *dst_addr,
                               struct cma_hdr *hdr,
                               __be16 local_port)
 {
-        struct sockaddr_in *ip4;
-
         if (src_addr) {
-                ip4 = (struct sockaddr_in *)src_addr;
-                ip4->sin_family = AF_INET;
-                ip4->sin_addr.s_addr = hdr->dst_addr.ip4.addr;
-                ip4->sin_port = local_port;
+                *src_addr = (struct sockaddr_in) {
+                        .sin_family = AF_INET,
+                        .sin_addr.s_addr = hdr->dst_addr.ip4.addr,
+                        .sin_port = local_port,
+                };
         }
 
         if (dst_addr) {
-                ip4 = (struct sockaddr_in *)dst_addr;
-                ip4->sin_family = AF_INET;
-                ip4->sin_addr.s_addr = hdr->src_addr.ip4.addr;
-                ip4->sin_port = hdr->port;
+                *dst_addr = (struct sockaddr_in) {
+                        .sin_family = AF_INET,
+                        .sin_addr.s_addr = hdr->src_addr.ip4.addr,
+                        .sin_port = hdr->port,
+                };
         }
 }
 
-static void cma_save_ip6_info(struct sockaddr *src_addr,
-                              struct sockaddr *dst_addr,
+static void cma_save_ip6_info(struct sockaddr_in6 *src_addr,
+                              struct sockaddr_in6 *dst_addr,
                               struct cma_hdr *hdr,
                               __be16 local_port)
 {
-        struct sockaddr_in6 *ip6;
-
         if (src_addr) {
-                ip6 = (struct sockaddr_in6 *)src_addr;
-                ip6->sin6_family = AF_INET6;
-                ip6->sin6_addr = hdr->dst_addr.ip6;
-                ip6->sin6_port = local_port;
+                *src_addr = (struct sockaddr_in6) {
+                        .sin6_family = AF_INET6,
+                        .sin6_addr = hdr->dst_addr.ip6,
+                        .sin6_port = local_port,
+                };
         }
 
         if (dst_addr) {
-                ip6 = (struct sockaddr_in6 *)dst_addr;
-                ip6->sin6_family = AF_INET6;
-                ip6->sin6_addr = hdr->src_addr.ip6;
-                ip6->sin6_port = hdr->port;
+                *dst_addr = (struct sockaddr_in6) {
+                        .sin6_family = AF_INET6,
+                        .sin6_addr = hdr->src_addr.ip6,
+                        .sin6_port = hdr->port,
+                };
         }
 }
 
@@ -1159,10 +1159,12 @@ static int cma_save_ip_info(struct sockaddr *src_addr,
 
         switch (cma_get_ip_ver(hdr)) {
         case 4:
-                cma_save_ip4_info(src_addr, dst_addr, hdr, port);
+                cma_save_ip4_info((struct sockaddr_in *)src_addr,
+                                  (struct sockaddr_in *)dst_addr, hdr, port);
                 break;
         case 6:
-                cma_save_ip6_info(src_addr, dst_addr, hdr, port);
+                cma_save_ip6_info((struct sockaddr_in6 *)src_addr,
+                                  (struct sockaddr_in6 *)dst_addr, hdr, port);
                 break;
         default:
                 return -EAFNOSUPPORT;
diff --git a/drivers/media/i2c/ir-kbd-i2c.c b/drivers/media/i2c/ir-kbd-i2c.c
index f95a6bc839d5..cede3975d04b 100644
--- a/drivers/media/i2c/ir-kbd-i2c.c
+++ b/drivers/media/i2c/ir-kbd-i2c.c
@@ -118,7 +118,7 @@ static int get_key_haup_common(struct IR_i2c *ir, enum rc_type *protocol,
                         *protocol = RC_TYPE_RC6_MCE;
                         dev &= 0x7f;
                         dprintk(1, "ir hauppauge (rc6-mce): t%d vendor=%d dev=%d code=%d\n",
-                                                toggle, vendor, dev, code);
+                                                *ptoggle, vendor, dev, code);
                 } else {
                         *ptoggle = 0;
                         *protocol = RC_TYPE_RC6_6A_32;
diff --git a/drivers/media/usb/dvb-usb/dib0700_core.c b/drivers/media/usb/dvb-usb/dib0700_core.c
index 92d5408684ac..47ce9d5de4c6 100644
--- a/drivers/media/usb/dvb-usb/dib0700_core.c
+++ b/drivers/media/usb/dvb-usb/dib0700_core.c
@@ -704,7 +704,7 @@ static void dib0700_rc_urb_completion(struct urb *purb)
         struct dvb_usb_device *d = purb->context;
         struct dib0700_rc_response *poll_reply;
         enum rc_type protocol;
-        u32 uninitialized_var(keycode);
+        u32 keycode;
         u8 toggle;
 
         deb_info("%s()\n", __func__);
@@ -745,7 +745,8 @@ static void dib0700_rc_urb_completion(struct urb *purb)
                     poll_reply->nec.data       == 0x00 &&
                     poll_reply->nec.not_data   == 0xff) {
                         poll_reply->data_state = 2;
-                        break;
+                        rc_repeat(d->rc_dev);
+                        goto resubmit;
                 }
 
                 if ((poll_reply->nec.data ^ poll_reply->nec.not_data) != 0xff) {
diff --git a/drivers/pcmcia/soc_common.c b/drivers/pcmcia/soc_common.c
index 153f3122283d..b6b316de055c 100644
--- a/drivers/pcmcia/soc_common.c
+++ b/drivers/pcmcia/soc_common.c
@@ -107,7 +107,7 @@ int soc_pcmcia_regulator_set(struct soc_pcmcia_socket *skt,
 
                 ret = regulator_enable(r->reg);
         } else {
-                regulator_disable(r->reg);
+                ret = regulator_disable(r->reg);
         }
         if (ret == 0)
                 r->on = on;
diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn
index 53449a6ff6aa..7c321a603b07 100644
--- a/scripts/Makefile.extrawarn
+++ b/scripts/Makefile.extrawarn
@@ -36,6 +36,7 @@ warning-2 += -Wshadow
 warning-2 += $(call cc-option, -Wlogical-op)
 warning-2 += $(call cc-option, -Wmissing-field-initializers)
 warning-2 += $(call cc-option, -Wsign-compare)
+warning-2 += $(call cc-option, -Wmaybe-uninitialized)
 
 warning-3 := -Wbad-function-cast
 warning-3 += -Wcast-qual
diff --git a/scripts/Makefile.ubsan b/scripts/Makefile.ubsan
index dd779c40c8e6..3b1b13818d59 100644
--- a/scripts/Makefile.ubsan
+++ b/scripts/Makefile.ubsan
@@ -17,4 +17,8 @@ endif
 ifdef CONFIG_UBSAN_NULL
       CFLAGS_UBSAN += $(call cc-option, -fsanitize=null)
 endif
+
+      # -fsanitize=* options makes GCC less smart than usual and
+      # increase number of 'maybe-uninitialized false-positives
+      CFLAGS_UBSAN += $(call cc-option, -Wno-maybe-uninitialized)
 endif