Merge android-4.4.148 (f057ff9) into msm-4.4

* refs/heads/tmp-f057ff9
  Linux 4.4.148
  x86/speculation/l1tf: Unbreak !__HAVE_ARCH_PFN_MODIFY_ALLOWED architectures
  x86/init: fix build with CONFIG_SWAP=n
  x86/speculation/l1tf: Fix up CPU feature flags
  x86/mm/kmmio: Make the tracer robust against L1TF
  x86/mm/pat: Make set_memory_np() L1TF safe
  x86/speculation/l1tf: Make pmd/pud_mknotpresent() invert
  x86/speculation/l1tf: Invert all not present mappings
  x86/speculation/l1tf: Fix up pte->pfn conversion for PAE
  x86/speculation/l1tf: Protect PAE swap entries against L1TF
  x86/cpufeatures: Add detection of L1D cache flush support.
  x86/speculation/l1tf: Extend 64bit swap file size limit
  x86/bugs: Move the l1tf function and define pr_fmt properly
  x86/speculation/l1tf: Limit swap file size to MAX_PA/2
  x86/speculation/l1tf: Disallow non privileged high MMIO PROT_NONE mappings
  mm: fix cache mode tracking in vm_insert_mixed()
  mm: Add vm_insert_pfn_prot()
  x86/speculation/l1tf: Add sysfs reporting for l1tf
  x86/speculation/l1tf: Make sure the first page is always reserved
  x86/speculation/l1tf: Protect PROT_NONE PTEs against speculation
  x86/speculation/l1tf: Protect swap entries against L1TF
  x86/speculation/l1tf: Change order of offset/type in swap entry
  mm: x86: move _PAGE_SWP_SOFT_DIRTY from bit 7 to bit 1
  x86/mm: Fix swap entry comment and macro
  x86/mm: Move swap offset/type up in PTE to work around erratum
  x86/speculation/l1tf: Increase 32bit PAE __PHYSICAL_PAGE_SHIFT
  x86/irqflags: Provide a declaration for native_save_fl
  kprobes/x86: Fix %p uses in error messages
  x86/speculation: Protect against userspace-userspace spectreRSB
  x86/paravirt: Fix spectre-v2 mitigations for paravirt guests
  ARM: dts: imx6sx: fix irq for pcie bridge
  IB/ocrdma: fix out of bounds access to local buffer
  IB/mlx4: Mark user MR as writable if actual virtual memory is writable
  IB/core: Make testing MR flags for writability a static inline function
  fix __legitimize_mnt()/mntput() race
  fix mntput/mntput race
  root dentries need RCU-delayed freeing
  scsi: sr: Avoid that opening a CD-ROM hangs with runtime power management enabled
  ACPI / LPSS: Add missing prv_offset setting for byt/cht PWM devices
  xen/netfront: don't cache skb_shinfo()
  parisc: Define mb() and add memory barriers to assembler unlock sequences
  parisc: Enable CONFIG_MLONGCALLS by default
  fork: unconditionally clear stack on fork
  ipv4+ipv6: Make INET*_ESP select CRYPTO_ECHAINIV
  tpm: fix race condition in tpm_common_write()
  ext4: fix check to prevent initializing reserved inodes
  Linux 4.4.147
  jfs: Fix inconsistency between memory allocation and ea_buf->max_size
  i2c: imx: Fix reinit_completion() use
  ring_buffer: tracing: Inherit the tracing setting to next ring buffer
  ACPI / PCI: Bail early in acpi_pci_add_bus() if there is no ACPI handle
  ext4: fix false negatives *and* false positives in ext4_check_descriptors()
  netlink: Don't shift on 64 for ngroups
  netlink: Don't shift with UB on nlk->ngroups
  netlink: Do not subscribe to non-existent groups
  nohz: Fix local_timer_softirq_pending()
  genirq: Make force irq threading setup more robust
  scsi: qla2xxx: Return error when TMF returns
  scsi: qla2xxx: Fix ISP recovery on unload

Conflicts:
	include/linux/swapfile.h

Removed CONFIG_CRYPTO_ECHAINIV from defconfig files since this upmerge is
adding this config to Kconfig file.

Change-Id: Ide96c29f919d76590c2bdccf356d1d464a892fd7
Signed-off-by: Srinivasarao P <spathi@codeaurora.org>

1 files changed, 26 insertions, 2 deletions

diff --git a/fs/namespace.c b/fs/namespace.c
index b3d8d3d8f05f..297ce252f39a 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -605,12 +605,21 @@ int __legitimize_mnt(struct vfsmount *bastard, unsigned seq)
 		return 0;
 	mnt = real_mount(bastard);
 	mnt_add_count(mnt, 1);
+	smp_mb();			// see mntput_no_expire()
 	if (likely(!read_seqretry(&mount_lock, seq)))
 		return 0;
 	if (bastard->mnt_flags & MNT_SYNC_UMOUNT) {
 		mnt_add_count(mnt, -1);
 		return 1;
 	}
+	lock_mount_hash();
+	if (unlikely(bastard->mnt_flags & MNT_DOOMED)) {
+		mnt_add_count(mnt, -1);
+		unlock_mount_hash();
+		return 1;
+	}
+	unlock_mount_hash();
+	/* caller will mntput() */
 	return -1;
 }
 
@@ -1142,12 +1151,27 @@ static DECLARE_DELAYED_WORK(delayed_mntput_work, delayed_mntput);
 static void mntput_no_expire(struct mount *mnt)
 {
 	rcu_read_lock();
-	mnt_add_count(mnt, -1);
-	if (likely(mnt->mnt_ns)) { /* shouldn't be the last one */
+	if (likely(READ_ONCE(mnt->mnt_ns))) {
+		/*
+		 * Since we don't do lock_mount_hash() here,
+		 * ->mnt_ns can change under us.  However, if it's
+		 * non-NULL, then there's a reference that won't
+		 * be dropped until after an RCU delay done after
+		 * turning ->mnt_ns NULL.  So if we observe it
+		 * non-NULL under rcu_read_lock(), the reference
+		 * we are dropping is not the final one.
+		 */
+		mnt_add_count(mnt, -1);
 		rcu_read_unlock();
 		return;
 	}
 	lock_mount_hash();
+	/*
+	 * make sure that if __legitimize_mnt() has not seen us grab
+	 * mount_lock, we'll see their refcount increment here.
+	 */
+	smp_mb();
+	mnt_add_count(mnt, -1);
 	if (mnt_get_count(mnt)) {
 		rcu_read_unlock();
 		unlock_mount_hash();