4.19.124, drop GCC10 patches that are now upstream

7 files changed, 8 insertions, 448 deletions

diff --git a/.SRCINFO b/.SRCINFO
index 3a3d9cfcc096..812ae5852004 100644
--- a/.SRCINFO
+++ b/.SRCINFO
@@ -1,7 +1,7 @@
 pkgbase = linux-lts419
 	pkgdesc = LTS 4.19 Linux
-	pkgver = 4.19.123
-	pkgrel = 2
+	pkgver = 4.19.124
+	pkgrel = 1
 	url = https://www.kernel.org/
 	arch = x86_64
 	license = GPL2
@@ -15,23 +15,13 @@ pkgbase = linux-lts419
 	makedepends = imagemagick
 	options = !strip
 	source = https://www.kernel.org/pub/linux/kernel/v4.x/linux-4.19.tar.xz
-	source = https://www.kernel.org/pub/linux/kernel/v4.x/patch-4.19.123.xz
+	source = https://www.kernel.org/pub/linux/kernel/v4.x/patch-4.19.124.xz
 	source = config
 	source = 0001-ZEN-Add-sysctl-and-CONFIG-to-disallow-unprivileged-C.patch
-	source = gcc-10-avoid-shadowing-standard-library-free-in-crypto.patch
-	source = gcc-10-drop_monitor-work-around-stringop-overflow-wa.patch
-	source = gcc-10-netfilter-conntrack-avoid-zero-length-bounds-.patch
-	source = gcc-10-warnings-fix-low-hanging-fruit.patch
-	source = gcc-10-x86-fix-early-boot-crash-third-try.patch
 	sha256sums = 0c68f5655528aed4f99dae71a5b259edc93239fa899e2df79c055275c21749a1
-	sha256sums = 56f4e052883a0030958bb0abfc54a1a28b3867090c9c8a563c203826deaf1ece
+	sha256sums = 3f0f43ca3cb4eba7441d57cd3f9bb3d27721f8ffcef2d64469faaff2846f7f95
 	sha256sums = 4e68572e7cc4c5368f0236e0792660ae8498373988625dca46e509399a7eaea6
 	sha256sums = a13581d3c6dc595206e4fe7fcf6b542e7a1bdbe96101f0f010fc5be49f99baf2
-	sha256sums = bf1ece4b16b233283d82d97b478012bfbb72e48604b55f78ce1ac076b0f9bcb4
-	sha256sums = 25517134bfb5eba79cea86fcd777a4a6a1d6cbfb2ee57656d8ffc6a910a0dfc3
-	sha256sums = ed3d9ee9c55e0b33aa7e4b75305e2d43f94aef071a90c276957e17483334710a
-	sha256sums = 81193a452440cf2040266ad33d204193176d0079d4ed3f7b92eaf45e0638a976
-	sha256sums = 59c0397a8556f518e89a3349e41b9eea983ee7d6e10afc39c9371edefd39a9ae
 
 pkgname = linux-lts419
 	pkgdesc = The LTS 4.19 Linux kernel and modules
diff --git a/PKGBUILD b/PKGBUILD
index a50a87b60e2b..63f527669c39 100644
--- a/PKGBUILD
+++ b/PKGBUILD
@@ -3,8 +3,8 @@
 pkgbase=linux-lts419
 _basever=4.19
 _srcname=linux-$_basever
-pkgver=${_basever}.123
-pkgrel=2
+pkgver=${_basever}.124
+pkgrel=1
 pkgdesc='LTS 4.19 Linux'
 url="https://www.kernel.org/"
 arch=(x86_64)
@@ -19,11 +19,6 @@ source=(
   https://www.kernel.org/pub/linux/kernel/v${pkgver%%.*}.x/patch-${pkgver}.xz #signature is mising
   config         # the main kernel config file
   0001-ZEN-Add-sysctl-and-CONFIG-to-disallow-unprivileged-C.patch
-  gcc-10-avoid-shadowing-standard-library-free-in-crypto.patch
-  gcc-10-drop_monitor-work-around-stringop-overflow-wa.patch
-  gcc-10-netfilter-conntrack-avoid-zero-length-bounds-.patch
-  gcc-10-warnings-fix-low-hanging-fruit.patch
-  gcc-10-x86-fix-early-boot-crash-third-try.patch
 )
 #validpgpkeys=(
 #  'ABAF11C65A2970B130ABE3C479BE3E4300411886'  # Linus Torvalds
@@ -31,14 +26,9 @@ source=(
 #)
 # https://www.kernel.org/pub/linux/kernel/v4.x/sha256sums.asc
 sha256sums=('0c68f5655528aed4f99dae71a5b259edc93239fa899e2df79c055275c21749a1'
-            '56f4e052883a0030958bb0abfc54a1a28b3867090c9c8a563c203826deaf1ece'
+            '3f0f43ca3cb4eba7441d57cd3f9bb3d27721f8ffcef2d64469faaff2846f7f95'
             '4e68572e7cc4c5368f0236e0792660ae8498373988625dca46e509399a7eaea6'
-            'a13581d3c6dc595206e4fe7fcf6b542e7a1bdbe96101f0f010fc5be49f99baf2'
-            'bf1ece4b16b233283d82d97b478012bfbb72e48604b55f78ce1ac076b0f9bcb4'
-            '25517134bfb5eba79cea86fcd777a4a6a1d6cbfb2ee57656d8ffc6a910a0dfc3'
-            'ed3d9ee9c55e0b33aa7e4b75305e2d43f94aef071a90c276957e17483334710a'
-            '81193a452440cf2040266ad33d204193176d0079d4ed3f7b92eaf45e0638a976'
-            '59c0397a8556f518e89a3349e41b9eea983ee7d6e10afc39c9371edefd39a9ae')
+            'a13581d3c6dc595206e4fe7fcf6b542e7a1bdbe96101f0f010fc5be49f99baf2')
 
 export KBUILD_BUILD_HOST=archlinux
 export KBUILD_BUILD_USER=$pkgbase
diff --git a/gcc-10-avoid-shadowing-standard-library-free-in-crypto.patch b/gcc-10-avoid-shadowing-standard-library-free-in-crypto.patch
deleted file mode 100644
index e556f3f92262..000000000000
--- a/gcc-10-avoid-shadowing-standard-library-free-in-crypto.patch
+++ /dev/null
@@ -1,87 +0,0 @@
-From 1a263ae60b04de959d9ce9caea4889385eefcc7b Mon Sep 17 00:00:00 2001
-From: Linus Torvalds <torvalds@linux-foundation.org>
-Date: Sat, 9 May 2020 15:58:04 -0700
-Subject: gcc-10: avoid shadowing standard library 'free()' in crypto
-MIME-Version: 1.0
-Content-Type: text/plain; charset=UTF-8
-Content-Transfer-Encoding: 8bit
-
-From: Linus Torvalds <torvalds@linux-foundation.org>
-
-commit 1a263ae60b04de959d9ce9caea4889385eefcc7b upstream.
-
-gcc-10 has started warning about conflicting types for a few new
-built-in functions, particularly 'free()'.
-
-This results in warnings like:
-
-   crypto/xts.c:325:13: warning: conflicting types for built-in function ‘free’; expected ‘void(void *)’ [-Wbuiltin-declaration-mismatch]
-
-because the crypto layer had its local freeing functions called
-'free()'.
-
-Gcc-10 is in the wrong here, since that function is marked 'static', and
-thus there is no chance of confusion with any standard library function
-namespace.
-
-But the simplest thing to do is to just use a different name here, and
-avoid this gcc mis-feature.
-
-[ Side note: gcc knowing about 'free()' is in itself not the
-  mis-feature: the semantics of 'free()' are special enough that a
-  compiler can validly do special things when seeing it.
-
-  So the mis-feature here is that gcc thinks that 'free()' is some
-  restricted name, and you can't shadow it as a local static function.
-
-  Making the special 'free()' semantics be a function attribute rather
-  than tied to the name would be the much better model ]
-
-Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-
----
- crypto/lrw.c |    4 ++--
- crypto/xts.c |    4 ++--
- 2 files changed, 4 insertions(+), 4 deletions(-)
-
---- a/crypto/lrw.c
-+++ b/crypto/lrw.c
-@@ -453,7 +453,7 @@ static void exit_tfm(struct crypto_skcip
- 	crypto_free_skcipher(ctx->child);
- }
- 
--static void free(struct skcipher_instance *inst)
-+static void free_inst(struct skcipher_instance *inst)
- {
- 	crypto_drop_skcipher(skcipher_instance_ctx(inst));
- 	kfree(inst);
-@@ -565,7 +565,7 @@ static int create(struct crypto_template
- 	inst->alg.encrypt = encrypt;
- 	inst->alg.decrypt = decrypt;
- 
--	inst->free = free;
-+	inst->free = free_inst;
- 
- 	err = skcipher_register_instance(tmpl, inst);
- 	if (err)
---- a/crypto/xts.c
-+++ b/crypto/xts.c
-@@ -393,7 +393,7 @@ static void exit_tfm(struct crypto_skcip
- 	crypto_free_cipher(ctx->tweak);
- }
- 
--static void free(struct skcipher_instance *inst)
-+static void free_inst(struct skcipher_instance *inst)
- {
- 	crypto_drop_skcipher(skcipher_instance_ctx(inst));
- 	kfree(inst);
-@@ -504,7 +504,7 @@ static int create(struct crypto_template
- 	inst->alg.encrypt = encrypt;
- 	inst->alg.decrypt = decrypt;
- 
--	inst->free = free;
-+	inst->free = free_inst;
- 
- 	err = skcipher_register_instance(tmpl, inst);
- 	if (err)
diff --git a/gcc-10-drop_monitor-work-around-stringop-overflow-wa.patch b/gcc-10-drop_monitor-work-around-stringop-overflow-wa.patch
deleted file mode 100644
index 8aaeaf34bf69..000000000000
--- a/gcc-10-drop_monitor-work-around-stringop-overflow-wa.patch
+++ /dev/null
@@ -1,73 +0,0 @@
-From 440d43ac6705396c96694a30847a6728da79a76d Mon Sep 17 00:00:00 2001
-From: Sasha Levin <sashal@kernel.org>
-Date: Thu, 30 Apr 2020 23:30:49 +0200
-Subject: drop_monitor: work around gcc-10 stringop-overflow warning
-
-From: Arnd Bergmann <arnd@arndb.de>
-
-[ Upstream commit dc30b4059f6e2abf3712ab537c8718562b21c45d ]
-
-The current gcc-10 snapshot produces a false-positive warning:
-
-net/core/drop_monitor.c: In function 'trace_drop_common.constprop':
-cc1: error: writing 8 bytes into a region of size 0 [-Werror=stringop-overflow=]
-In file included from net/core/drop_monitor.c:23:
-include/uapi/linux/net_dropmon.h:36:8: note: at offset 0 to object 'entries' with size 4 declared here
-   36 |  __u32 entries;
-      |        ^~~~~~~
-
-I reported this in the gcc bugzilla, but in case it does not get
-fixed in the release, work around it by using a temporary variable.
-
-Fixes: 9a8afc8d3962 ("Network Drop Monitor: Adding drop monitor implementation & Netlink protocol")
-Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94881
-Signed-off-by: Arnd Bergmann <arnd@arndb.de>
-Acked-by: Neil Horman <nhorman@tuxdriver.com>
-Signed-off-by: David S. Miller <davem@davemloft.net>
-Signed-off-by: Sasha Levin <sashal@kernel.org>
----
- net/core/drop_monitor.c | 11 +++++++----
- 1 file changed, 7 insertions(+), 4 deletions(-)
-
-diff --git a/net/core/drop_monitor.c b/net/core/drop_monitor.c
-index c7785efeea577..3978a5e8d261c 100644
---- a/net/core/drop_monitor.c
-+++ b/net/core/drop_monitor.c
-@@ -154,6 +154,7 @@ static void sched_send_work(struct timer_list *t)
- static void trace_drop_common(struct sk_buff *skb, void *location)
- {
- 	struct net_dm_alert_msg *msg;
-+	struct net_dm_drop_point *point;
- 	struct nlmsghdr *nlh;
- 	struct nlattr *nla;
- 	int i;
-@@ -172,11 +173,13 @@ static void trace_drop_common(struct sk_buff *skb, void *location)
- 	nlh = (struct nlmsghdr *)dskb->data;
- 	nla = genlmsg_data(nlmsg_data(nlh));
- 	msg = nla_data(nla);
-+	point = msg->points;
- 	for (i = 0; i < msg->entries; i++) {
--		if (!memcmp(&location, msg->points[i].pc, sizeof(void *))) {
--			msg->points[i].count++;
-+		if (!memcmp(&location, &point->pc, sizeof(void *))) {
-+			point->count++;
- 			goto out;
- 		}
-+		point++;
- 	}
- 	if (msg->entries == dm_hit_limit)
- 		goto out;
-@@ -185,8 +188,8 @@ static void trace_drop_common(struct sk_buff *skb, void *location)
- 	 */
- 	__nla_reserve_nohdr(dskb, sizeof(struct net_dm_drop_point));
- 	nla->nla_len += NLA_ALIGN(sizeof(struct net_dm_drop_point));
--	memcpy(msg->points[msg->entries].pc, &location, sizeof(void *));
--	msg->points[msg->entries].count = 1;
-+	memcpy(point->pc, &location, sizeof(void *));
-+	point->count = 1;
- 	msg->entries++;
- 
- 	if (!timer_pending(&data->send_timer)) {
--- 
-2.20.1
-
diff --git a/gcc-10-netfilter-conntrack-avoid-zero-length-bounds-.patch b/gcc-10-netfilter-conntrack-avoid-zero-length-bounds-.patch
deleted file mode 100644
index 7f2817624be3..000000000000
--- a/gcc-10-netfilter-conntrack-avoid-zero-length-bounds-.patch
+++ /dev/null
@@ -1,66 +0,0 @@
-From 81a29e2184eb24bc468233eacc09e59dadf0c95d Mon Sep 17 00:00:00 2001
-From: Sasha Levin <sashal@kernel.org>
-Date: Thu, 30 Apr 2020 23:30:48 +0200
-Subject: netfilter: conntrack: avoid gcc-10 zero-length-bounds warning
-
-From: Arnd Bergmann <arnd@arndb.de>
-
-[ Upstream commit 2c407aca64977ede9b9f35158e919773cae2082f ]
-
-gcc-10 warns around a suspicious access to an empty struct member:
-
-net/netfilter/nf_conntrack_core.c: In function '__nf_conntrack_alloc':
-net/netfilter/nf_conntrack_core.c:1522:9: warning: array subscript 0 is outside the bounds of an interior zero-length array 'u8[0]' {aka 'unsigned char[0]'} [-Wzero-length-bounds]
- 1522 |  memset(&ct->__nfct_init_offset[0], 0,
-      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~
-In file included from net/netfilter/nf_conntrack_core.c:37:
-include/net/netfilter/nf_conntrack.h:90:5: note: while referencing '__nfct_init_offset'
-   90 |  u8 __nfct_init_offset[0];
-      |     ^~~~~~~~~~~~~~~~~~
-
-The code is correct but a bit unusual. Rework it slightly in a way that
-does not trigger the warning, using an empty struct instead of an empty
-array. There are probably more elegant ways to do this, but this is the
-smallest change.
-
-Fixes: c41884ce0562 ("netfilter: conntrack: avoid zeroing timer")
-Signed-off-by: Arnd Bergmann <arnd@arndb.de>
-Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
-Signed-off-by: Sasha Levin <sashal@kernel.org>
----
- include/net/netfilter/nf_conntrack.h | 2 +-
- net/netfilter/nf_conntrack_core.c    | 4 ++--
- 2 files changed, 3 insertions(+), 3 deletions(-)
-
-diff --git a/include/net/netfilter/nf_conntrack.h b/include/net/netfilter/nf_conntrack.h
-index f45141bdbb837..ac4d70aeee129 100644
---- a/include/net/netfilter/nf_conntrack.h
-+++ b/include/net/netfilter/nf_conntrack.h
-@@ -85,7 +85,7 @@ struct nf_conn {
- 	struct hlist_node	nat_bysource;
- #endif
- 	/* all members below initialized via memset */
--	u8 __nfct_init_offset[0];
-+	struct { } __nfct_init_offset;
- 
- 	/* If we were expected by an expectation, this will be it */
- 	struct nf_conn *master;
-diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
-index c6073d17c3244..ad1da6b2fb607 100644
---- a/net/netfilter/nf_conntrack_core.c
-+++ b/net/netfilter/nf_conntrack_core.c
-@@ -1352,9 +1352,9 @@ __nf_conntrack_alloc(struct net *net,
- 	*(unsigned long *)(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev) = hash;
- 	ct->status = 0;
- 	write_pnet(&ct->ct_net, net);
--	memset(&ct->__nfct_init_offset[0], 0,
-+	memset(&ct->__nfct_init_offset, 0,
- 	       offsetof(struct nf_conn, proto) -
--	       offsetof(struct nf_conn, __nfct_init_offset[0]));
-+	       offsetof(struct nf_conn, __nfct_init_offset));
- 
- 	nf_ct_zone_add(ct, zone);
- 
--- 
-2.20.1
-
diff --git a/gcc-10-warnings-fix-low-hanging-fruit.patch b/gcc-10-warnings-fix-low-hanging-fruit.patch
deleted file mode 100644
index a8a51ee681f0..000000000000
--- a/gcc-10-warnings-fix-low-hanging-fruit.patch
+++ /dev/null
@@ -1,50 +0,0 @@
-From 9d82973e032e246ff5663c9805fbb5407ae932e3 Mon Sep 17 00:00:00 2001
-From: Linus Torvalds <torvalds@linux-foundation.org>
-Date: Mon, 4 May 2020 09:16:37 -0700
-Subject: gcc-10 warnings: fix low-hanging fruit
-
-From: Linus Torvalds <torvalds@linux-foundation.org>
-
-commit 9d82973e032e246ff5663c9805fbb5407ae932e3 upstream.
-
-Due to a bug-report that was compiler-dependent, I updated one of my
-machines to gcc-10.  That shows a lot of new warnings.  Happily they
-seem to be mostly the valid kind, but it's going to cause a round of
-churn for getting rid of them..
-
-This is the really low-hanging fruit of removing a couple of zero-sized
-arrays in some core code.  We have had a round of these patches before,
-and we'll have many more coming, and there is nothing special about
-these except that they were particularly trivial, and triggered more
-warnings than most.
-
-Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-
----
- include/linux/fs.h  |    2 +-
- include/linux/tty.h |    2 +-
- 2 files changed, 2 insertions(+), 2 deletions(-)
-
---- a/include/linux/fs.h
-+++ b/include/linux/fs.h
-@@ -934,7 +934,7 @@ struct file_handle {
- 	__u32 handle_bytes;
- 	int handle_type;
- 	/* file identifier */
--	unsigned char f_handle[0];
-+	unsigned char f_handle[];
- };
- 
- static inline struct file *get_file(struct file *f)
---- a/include/linux/tty.h
-+++ b/include/linux/tty.h
-@@ -66,7 +66,7 @@ struct tty_buffer {
- 	int read;
- 	int flags;
- 	/* Data points here */
--	unsigned long data[0];
-+	unsigned long data[];
- };
- 
- /* Values for .flags field of tty_buffer */
diff --git a/gcc-10-x86-fix-early-boot-crash-third-try.patch b/gcc-10-x86-fix-early-boot-crash-third-try.patch
deleted file mode 100644
index df7fb67304c7..000000000000
--- a/gcc-10-x86-fix-early-boot-crash-third-try.patch
+++ /dev/null
@@ -1,144 +0,0 @@
-From a9a3ed1eff3601b63aea4fb462d8b3b92c7c1e7e Mon Sep 17 00:00:00 2001
-From: Borislav Petkov <bp@suse.de>
-Date: Wed, 22 Apr 2020 18:11:30 +0200
-Subject: x86: Fix early boot crash on gcc-10, third try
-MIME-Version: 1.0
-Content-Type: text/plain; charset=UTF-8
-Content-Transfer-Encoding: 8bit
-
-From: Borislav Petkov <bp@suse.de>
-
-commit a9a3ed1eff3601b63aea4fb462d8b3b92c7c1e7e upstream.
-
-... or the odyssey of trying to disable the stack protector for the
-function which generates the stack canary value.
-
-The whole story started with Sergei reporting a boot crash with a kernel
-built with gcc-10:
-
-  Kernel panic — not syncing: stack-protector: Kernel stack is corrupted in: start_secondary
-  CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.6.0-rc5—00235—gfffb08b37df9 #139
-  Hardware name: Gigabyte Technology Co., Ltd. To be filled by O.E.M./H77M—D3H, BIOS F12 11/14/2013
-  Call Trace:
-    dump_stack
-    panic
-    ? start_secondary
-    __stack_chk_fail
-    start_secondary
-    secondary_startup_64
-  -—-[ end Kernel panic — not syncing: stack—protector: Kernel stack is corrupted in: start_secondary
-
-This happens because gcc-10 tail-call optimizes the last function call
-in start_secondary() - cpu_startup_entry() - and thus emits a stack
-canary check which fails because the canary value changes after the
-boot_init_stack_canary() call.
-
-To fix that, the initial attempt was to mark the one function which
-generates the stack canary with:
-
-  __attribute__((optimize("-fno-stack-protector"))) ... start_secondary(void *unused)
-
-however, using the optimize attribute doesn't work cumulatively
-as the attribute does not add to but rather replaces previously
-supplied optimization options - roughly all -fxxx options.
-
-The key one among them being -fno-omit-frame-pointer and thus leading to
-not present frame pointer - frame pointer which the kernel needs.
-
-The next attempt to prevent compilers from tail-call optimizing
-the last function call cpu_startup_entry(), shy of carving out
-start_secondary() into a separate compilation unit and building it with
--fno-stack-protector, was to add an empty asm("").
-
-This current solution was short and sweet, and reportedly, is supported
-by both compilers but we didn't get very far this time: future (LTO?)
-optimization passes could potentially eliminate this, which leads us
-to the third attempt: having an actual memory barrier there which the
-compiler cannot ignore or move around etc.
-
-That should hold for a long time, but hey we said that about the other
-two solutions too so...
-
-Reported-by: Sergei Trofimovich <slyfox@gentoo.org>
-Signed-off-by: Borislav Petkov <bp@suse.de>
-Tested-by: Kalle Valo <kvalo@codeaurora.org>
-Cc: <stable@vger.kernel.org>
-Link: https://lkml.kernel.org/r/20200314164451.346497-1-slyfox@gentoo.org
-Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-
----
- arch/x86/include/asm/stackprotector.h |    7 ++++++-
- arch/x86/kernel/smpboot.c             |    8 ++++++++
- arch/x86/xen/smp_pv.c                 |    1 +
- include/linux/compiler.h              |    6 ++++++
- init/main.c                           |    2 ++
- 5 files changed, 23 insertions(+), 1 deletion(-)
-
---- a/arch/x86/include/asm/stackprotector.h
-+++ b/arch/x86/include/asm/stackprotector.h
-@@ -55,8 +55,13 @@
- /*
-  * Initialize the stackprotector canary value.
-  *
-- * NOTE: this must only be called from functions that never return,
-+ * NOTE: this must only be called from functions that never return
-  * and it must always be inlined.
-+ *
-+ * In addition, it should be called from a compilation unit for which
-+ * stack protector is disabled. Alternatively, the caller should not end
-+ * with a function call which gets tail-call optimized as that would
-+ * lead to checking a modified canary value.
-  */
- static __always_inline void boot_init_stack_canary(void)
- {
---- a/arch/x86/kernel/smpboot.c
-+++ b/arch/x86/kernel/smpboot.c
-@@ -269,6 +269,14 @@ static void notrace start_secondary(void
- 
- 	wmb();
- 	cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
-+
-+	/*
-+	 * Prevent tail call to cpu_startup_entry() because the stack protector
-+	 * guard has been changed a couple of function calls up, in
-+	 * boot_init_stack_canary() and must not be checked before tail calling
-+	 * another function.
-+	 */
-+	prevent_tail_call_optimization();
- }
- 
- /**
---- a/arch/x86/xen/smp_pv.c
-+++ b/arch/x86/xen/smp_pv.c
-@@ -89,6 +89,7 @@ asmlinkage __visible void cpu_bringup_an
- {
- 	cpu_bringup();
- 	cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
-+	prevent_tail_call_optimization();
- }
- 
- void xen_smp_intr_free_pv(unsigned int cpu)
---- a/include/linux/compiler.h
-+++ b/include/linux/compiler.h
-@@ -351,4 +351,10 @@ static inline void *offset_to_ptr(const
- 	compiletime_assert(__native_word(t),				\
- 		"Need native word sized stores/loads for atomicity.")
- 
-+/*
-+ * This is needed in functions which generate the stack canary, see
-+ * arch/x86/kernel/smpboot.c::start_secondary() for an example.
-+ */
-+#define prevent_tail_call_optimization()	mb()
-+
- #endif /* __LINUX_COMPILER_H */
---- a/init/main.c
-+++ b/init/main.c
-@@ -735,6 +735,8 @@ asmlinkage __visible void __init start_k
- 
- 	/* Do the rest non-__init'ed, we're now alive */
- 	rest_init();
-+
-+	prevent_tail_call_optimization();
- }
- 
- /* Call all constructor functions linked into the kernel. */