Patch "sparc64: Take ctx_alloc_lock properly in hugetlb_setup()." has been added to the 4.4-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    sparc64: Take ctx_alloc_lock properly in hugetlb_setup().

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     sparc64-take-ctx_alloc_lock-properly-in-hugetlb_setup.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Mon Jun 20 10:48:29 PDT 2016
From: "David S. Miller" <davem@davemloft.net>
Date: Wed, 25 May 2016 12:51:20 -0700
Subject: sparc64: Take ctx_alloc_lock properly in hugetlb_setup().

From: "David S. Miller" <davem@davemloft.net>

[ Upstream commit 9ea46abe22550e3366ff7cee2f8391b35b12f730 ]

On cheetahplus chips we take the ctx_alloc_lock in order to
modify the TLB lookup parameters for the indexed TLBs, which
are stored in the context register.

This is called with interrupts disabled, however ctx_alloc_lock
is an IRQ safe lock, therefore we must take acquire/release it
properly with spin_{lock,unlock}_irq().

Reported-by: Meelis Roos <mroos@linux.ee>
Tested-by: Meelis Roos <mroos@linux.ee>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/sparc/mm/init_64.c |   10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

--- a/arch/sparc/mm/init_64.c
+++ b/arch/sparc/mm/init_64.c
@@ -2821,9 +2821,10 @@ void hugetlb_setup(struct pt_regs *regs)
 	 * the Data-TLB for huge pages.
 	 */
 	if (tlb_type == cheetah_plus) {
+		bool need_context_reload = false;
 		unsigned long ctx;
 
-		spin_lock(&ctx_alloc_lock);
+		spin_lock_irq(&ctx_alloc_lock);
 		ctx = mm->context.sparc64_ctx_val;
 		ctx &= ~CTX_PGSZ_MASK;
 		ctx |= CTX_PGSZ_BASE << CTX_PGSZ0_SHIFT;
@@ -2842,9 +2843,12 @@ void hugetlb_setup(struct pt_regs *regs)
 			 * also executing in this address space.
 			 */
 			mm->context.sparc64_ctx_val = ctx;
-			on_each_cpu(context_reload, mm, 0);
+			need_context_reload = true;
 		}
-		spin_unlock(&ctx_alloc_lock);
+		spin_unlock_irq(&ctx_alloc_lock);
+
+		if (need_context_reload)
+			on_each_cpu(context_reload, mm, 0);
 	}
 }
 #endif


Patches currently in stable-queue which might be from davem@davemloft.net are

queue-4.4/sparc64-fix-bootup-regressions-on-some-kconfig-combinations.patch
queue-4.4/bpf-inode-disallow-userns-mounts.patch
queue-4.4/vxlan-accept-user-specified-mtu-value-when-create-new-vxlan-link.patch
queue-4.4/sfc-on-mc-reset-clear-pio-buffer-linkage-in-txqs.patch
queue-4.4/ipv6-skip-xfrm-lookup-if-dst_entry-in-socket-cache-is-valid.patch
queue-4.4/l2tp-fix-configuration-passed-to-setup_udp_tunnel_sock.patch
queue-4.4/switchdev-pass-pointer-to-fib_info-instead-of-copy.patch
queue-4.4/vxlan-relax-mtu-constraints.patch
queue-4.4/sparc-fix-system-call-tracing-register-handling.patch
queue-4.4/vxlan-gre-geneve-set-a-large-mtu-on-ovs-created-tunnel-devices.patch
queue-4.4/tcp-record-tlp-and-er-timer-stats-in-v6-stats.patch
queue-4.4/sparc64-fix-return-from-trap-window-fill-crashes.patch
queue-4.4/bpf-use-mount_nodev-not-mount_ns-to-mount-the-bpf-filesystem.patch
queue-4.4/netlink-fix-dump-skb-leak-double-free.patch
queue-4.4/sparc-pci-fix-for-panic-while-enabling-sr-iov.patch
queue-4.4/team-don-t-call-netdev_change_features-under-team-lock.patch
queue-4.4/sparc64-reduce-tlb-flushes-during-hugepte-changes.patch
queue-4.4/udp-prevent-skbs-lingering-in-tunnel-socket-queues.patch
queue-4.4/bridge-don-t-insert-unnecessary-local-fdb-entry-on-changing-mac-address.patch
queue-4.4/tipc-fix-nametable-publication-field-in-nl-compat.patch
queue-4.4/sparc64-fix-sparc64_set_context-stack-handling.patch
queue-4.4/sparc64-take-ctx_alloc_lock-properly-in-hugetlb_setup.patch
queue-4.4/tipc-check-nl-sock-before-parsing-nested-attributes.patch
queue-4.4/geneve-relax-mtu-constraints.patch
queue-4.4/uapi-glibc-compat-fix-compilation-when-__use_misc-in-glibc.patch
queue-4.4/sparc-harden-signal-return-frame-checks.patch
queue-4.4/tuntap-correctly-wake-up-process-during-uninit.patch
queue-4.4/sparc64-fix-numa-node-distance-initialization.patch