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Message-Id: <1409334332-22902-2-git-send-email-kamal@canonical.com>
Date: Fri, 29 Aug 2014 10:45:32 -0700
From: Kamal Mostafa <kamal@...onical.com>
To: linux-kernel@...r.kernel.org, stable@...r.kernel.org,
kernel-team@...ts.ubuntu.com
Cc: lwn@....net
Subject: Re: [3.8.y.z extended stable] Linux 3.8.13.28
diff --git a/Makefile b/Makefile
index 5cc8641..7f7e383 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,7 @@
VERSION = 3
PATCHLEVEL = 8
SUBLEVEL = 13
-EXTRAVERSION = .27
+EXTRAVERSION = .28
NAME = Remoralised Urchins Update
# *DOCUMENTATION*
diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h
index 942a086..68e9f00 100644
--- a/arch/x86/include/asm/ptrace.h
+++ b/arch/x86/include/asm/ptrace.h
@@ -232,6 +232,22 @@ static inline unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs,
#define ARCH_HAS_USER_SINGLE_STEP_INFO
+/*
+ * When hitting ptrace_stop(), we cannot return using SYSRET because
+ * that does not restore the full CPU state, only a minimal set. The
+ * ptracer can change arbitrary register values, which is usually okay
+ * because the usual ptrace stops run off the signal delivery path which
+ * forces IRET; however, ptrace_event() stops happen in arbitrary places
+ * in the kernel and don't force IRET path.
+ *
+ * So force IRET path after a ptrace stop.
+ */
+#define arch_ptrace_stop_needed(code, info) \
+({ \
+ set_thread_flag(TIF_NOTIFY_RESUME); \
+ false; \
+})
+
struct user_desc;
extern int do_get_thread_area(struct task_struct *p, int idx,
struct user_desc __user *info);
diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S
index 60d03c2..1843543 100644
--- a/arch/x86/kernel/entry_32.S
+++ b/arch/x86/kernel/entry_32.S
@@ -434,8 +434,9 @@ sysenter_past_esp:
jnz sysenter_audit
sysenter_do_call:
cmpl $(NR_syscalls), %eax
- jae syscall_badsys
+ jae sysenter_badsys
call *sys_call_table(,%eax,4)
+sysenter_after_call:
movl %eax,PT_EAX(%esp)
LOCKDEP_SYS_EXIT
DISABLE_INTERRUPTS(CLBR_ANY)
@@ -516,6 +517,7 @@ ENTRY(system_call)
jae syscall_badsys
syscall_call:
call *sys_call_table(,%eax,4)
+syscall_after_call:
movl %eax,PT_EAX(%esp) # store the return value
syscall_exit:
LOCKDEP_SYS_EXIT
@@ -685,8 +687,13 @@ syscall_fault:
END(syscall_fault)
syscall_badsys:
- movl $-ENOSYS,PT_EAX(%esp)
- jmp resume_userspace
+ movl $-ENOSYS,%eax
+ jmp syscall_after_call
+END(syscall_badsys)
+
+sysenter_badsys:
+ movl $-ENOSYS,%eax
+ jmp sysenter_after_call
END(syscall_badsys)
CFI_ENDPROC
/*
diff --git a/drivers/target/target_core_rd.c b/drivers/target/target_core_rd.c
index 0457de3..51968ed 100644
--- a/drivers/target/target_core_rd.c
+++ b/drivers/target/target_core_rd.c
@@ -174,7 +174,7 @@ static int rd_build_device_space(struct rd_dev *rd_dev)
- 1;
for (j = 0; j < sg_per_table; j++) {
- pg = alloc_pages(GFP_KERNEL, 0);
+ pg = alloc_pages(GFP_KERNEL | __GFP_ZERO, 0);
if (!pg) {
pr_err("Unable to allocate scatterlist"
" pages for struct rd_dev_sg_table\n");
diff --git a/fs/namespace.c b/fs/namespace.c
index 5dd7709..4d63cfe 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -799,8 +799,21 @@ static struct mount *clone_mnt(struct mount *old, struct dentry *root,
mnt->mnt.mnt_flags = old->mnt.mnt_flags & ~MNT_WRITE_HOLD;
/* Don't allow unprivileged users to change mount flags */
- if ((flag & CL_UNPRIVILEGED) && (mnt->mnt.mnt_flags & MNT_READONLY))
- mnt->mnt.mnt_flags |= MNT_LOCK_READONLY;
+ if (flag & CL_UNPRIVILEGED) {
+ mnt->mnt.mnt_flags |= MNT_LOCK_ATIME;
+
+ if (mnt->mnt.mnt_flags & MNT_READONLY)
+ mnt->mnt.mnt_flags |= MNT_LOCK_READONLY;
+
+ if (mnt->mnt.mnt_flags & MNT_NODEV)
+ mnt->mnt.mnt_flags |= MNT_LOCK_NODEV;
+
+ if (mnt->mnt.mnt_flags & MNT_NOSUID)
+ mnt->mnt.mnt_flags |= MNT_LOCK_NOSUID;
+
+ if (mnt->mnt.mnt_flags & MNT_NOEXEC)
+ mnt->mnt.mnt_flags |= MNT_LOCK_NOEXEC;
+ }
atomic_inc(&sb->s_active);
mnt->mnt.mnt_sb = sb;
@@ -1740,9 +1753,6 @@ static int change_mount_flags(struct vfsmount *mnt, int ms_flags)
if (readonly_request == __mnt_is_readonly(mnt))
return 0;
- if (mnt->mnt_flags & MNT_LOCK_READONLY)
- return -EPERM;
-
if (readonly_request)
error = mnt_make_readonly(real_mount(mnt));
else
@@ -1771,6 +1781,33 @@ static int do_remount(struct path *path, int flags, int mnt_flags,
if (path->dentry != path->mnt->mnt_root)
return -EINVAL;
+ /* Don't allow changing of locked mnt flags.
+ *
+ * No locks need to be held here while testing the various
+ * MNT_LOCK flags because those flags can never be cleared
+ * once they are set.
+ */
+ if ((mnt->mnt.mnt_flags & MNT_LOCK_READONLY) &&
+ !(mnt_flags & MNT_READONLY)) {
+ return -EPERM;
+ }
+ if ((mnt->mnt.mnt_flags & MNT_LOCK_NODEV) &&
+ !(mnt_flags & MNT_NODEV)) {
+ return -EPERM;
+ }
+ if ((mnt->mnt.mnt_flags & MNT_LOCK_NOSUID) &&
+ !(mnt_flags & MNT_NOSUID)) {
+ return -EPERM;
+ }
+ if ((mnt->mnt.mnt_flags & MNT_LOCK_NOEXEC) &&
+ !(mnt_flags & MNT_NOEXEC)) {
+ return -EPERM;
+ }
+ if ((mnt->mnt.mnt_flags & MNT_LOCK_ATIME) &&
+ ((mnt->mnt.mnt_flags & MNT_ATIME_MASK) != (mnt_flags & MNT_ATIME_MASK))) {
+ return -EPERM;
+ }
+
err = security_sb_remount(sb, data);
if (err)
return err;
@@ -1782,7 +1819,7 @@ static int do_remount(struct path *path, int flags, int mnt_flags,
err = do_remount_sb(sb, flags, data, 0);
if (!err) {
br_write_lock(&vfsmount_lock);
- mnt_flags |= mnt->mnt.mnt_flags & MNT_PROPAGATION_MASK;
+ mnt_flags |= mnt->mnt.mnt_flags & ~MNT_USER_SETTABLE_MASK;
mnt->mnt.mnt_flags = mnt_flags;
br_write_unlock(&vfsmount_lock);
}
@@ -1971,7 +2008,7 @@ static int do_new_mount(struct path *path, const char *fstype, int flags,
*/
if (!(type->fs_flags & FS_USERNS_DEV_MOUNT)) {
flags |= MS_NODEV;
- mnt_flags |= MNT_NODEV;
+ mnt_flags |= MNT_NODEV | MNT_LOCK_NODEV;
}
}
@@ -2290,6 +2327,14 @@ long do_mount(const char *dev_name, const char *dir_name,
if (flags & MS_RDONLY)
mnt_flags |= MNT_READONLY;
+ /* The default atime for remount is preservation */
+ if ((flags & MS_REMOUNT) &&
+ ((flags & (MS_NOATIME | MS_NODIRATIME | MS_RELATIME |
+ MS_STRICTATIME)) == 0)) {
+ mnt_flags &= ~MNT_ATIME_MASK;
+ mnt_flags |= path.mnt->mnt_flags & MNT_ATIME_MASK;
+ }
+
flags &= ~(MS_NOSUID | MS_NOEXEC | MS_NODEV | MS_ACTIVE | MS_BORN |
MS_NOATIME | MS_NODIRATIME | MS_RELATIME| MS_KERNMOUNT |
MS_STRICTATIME);
diff --git a/include/linux/mount.h b/include/linux/mount.h
index 73005f9..f058e13 100644
--- a/include/linux/mount.h
+++ b/include/linux/mount.h
@@ -42,11 +42,18 @@ struct mnt_namespace;
* flag, consider how it interacts with shared mounts.
*/
#define MNT_SHARED_MASK (MNT_UNBINDABLE)
-#define MNT_PROPAGATION_MASK (MNT_SHARED | MNT_UNBINDABLE)
+#define MNT_USER_SETTABLE_MASK (MNT_NOSUID | MNT_NODEV | MNT_NOEXEC \
+ | MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME \
+ | MNT_READONLY)
+#define MNT_ATIME_MASK (MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME )
#define MNT_INTERNAL 0x4000
+#define MNT_LOCK_ATIME 0x040000
+#define MNT_LOCK_NOEXEC 0x080000
+#define MNT_LOCK_NOSUID 0x100000
+#define MNT_LOCK_NODEV 0x200000
#define MNT_LOCK_READONLY 0x400000
struct vfsmount {
diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h
index 2e99b8e..bb980ae 100644
--- a/include/linux/ptrace.h
+++ b/include/linux/ptrace.h
@@ -337,6 +337,9 @@ static inline void user_single_step_siginfo(struct task_struct *tsk,
* calling arch_ptrace_stop() when it would be superfluous. For example,
* if the thread has not been back to user mode since the last stop, the
* thread state might indicate that nothing needs to be done.
+ *
+ * This is guaranteed to be invoked once before a task stops for ptrace and
+ * may include arch-specific operations necessary prior to a ptrace stop.
*/
#define arch_ptrace_stop_needed(code, info) (0)
#endif
diff --git a/mm/shmem.c b/mm/shmem.c
index efd0b3a..840643a 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -78,11 +78,12 @@ static struct vfsmount *shm_mnt;
#define SHORT_SYMLINK_LEN 128
/*
- * shmem_fallocate and shmem_writepage communicate via inode->i_private
- * (with i_mutex making sure that it has only one user at a time):
- * we would prefer not to enlarge the shmem inode just for that.
+ * shmem_fallocate communicates with shmem_fault or shmem_writepage via
+ * inode->i_private (with i_mutex making sure that it has only one user at
+ * a time): we would prefer not to enlarge the shmem inode just for that.
*/
struct shmem_falloc {
+ wait_queue_head_t *waitq; /* faults into hole wait for punch to end */
pgoff_t start; /* start of range currently being fallocated */
pgoff_t next; /* the next page offset to be fallocated */
pgoff_t nr_falloced; /* how many new pages have been fallocated */
@@ -532,22 +533,19 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
return;
index = start;
- for ( ; ; ) {
+ while (index < end) {
cond_resched();
pvec.nr = shmem_find_get_pages_and_swap(mapping, index,
min(end - index, (pgoff_t)PAGEVEC_SIZE),
pvec.pages, indices);
if (!pvec.nr) {
- if (index == start || unfalloc)
+ /* If all gone or hole-punch or unfalloc, we're done */
+ if (index == start || end != -1)
break;
+ /* But if truncating, restart to make sure all gone */
index = start;
continue;
}
- if ((index == start || unfalloc) && indices[0] >= end) {
- shmem_deswap_pagevec(&pvec);
- pagevec_release(&pvec);
- break;
- }
mem_cgroup_uncharge_start();
for (i = 0; i < pagevec_count(&pvec); i++) {
struct page *page = pvec.pages[i];
@@ -559,8 +557,12 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
if (radix_tree_exceptional_entry(page)) {
if (unfalloc)
continue;
- nr_swaps_freed += !shmem_free_swap(mapping,
- index, page);
+ if (shmem_free_swap(mapping, index, page)) {
+ /* Swap was replaced by page: retry */
+ index--;
+ break;
+ }
+ nr_swaps_freed++;
continue;
}
@@ -569,6 +571,11 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
if (page->mapping == mapping) {
VM_BUG_ON(PageWriteback(page));
truncate_inode_page(mapping, page);
+ } else {
+ /* Page was replaced by swap: retry */
+ unlock_page(page);
+ index--;
+ break;
}
}
unlock_page(page);
@@ -825,6 +832,7 @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc)
spin_lock(&inode->i_lock);
shmem_falloc = inode->i_private;
if (shmem_falloc &&
+ !shmem_falloc->waitq &&
index >= shmem_falloc->start &&
index < shmem_falloc->next)
shmem_falloc->nr_unswapped++;
@@ -1299,6 +1307,64 @@ static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
int error;
int ret = VM_FAULT_LOCKED;
+ /*
+ * Trinity finds that probing a hole which tmpfs is punching can
+ * prevent the hole-punch from ever completing: which in turn
+ * locks writers out with its hold on i_mutex. So refrain from
+ * faulting pages into the hole while it's being punched. Although
+ * shmem_undo_range() does remove the additions, it may be unable to
+ * keep up, as each new page needs its own unmap_mapping_range() call,
+ * and the i_mmap tree grows ever slower to scan if new vmas are added.
+ *
+ * It does not matter if we sometimes reach this check just before the
+ * hole-punch begins, so that one fault then races with the punch:
+ * we just need to make racing faults a rare case.
+ *
+ * The implementation below would be much simpler if we just used a
+ * standard mutex or completion: but we cannot take i_mutex in fault,
+ * and bloating every shmem inode for this unlikely case would be sad.
+ */
+ if (unlikely(inode->i_private)) {
+ struct shmem_falloc *shmem_falloc;
+
+ spin_lock(&inode->i_lock);
+ shmem_falloc = inode->i_private;
+ if (shmem_falloc &&
+ shmem_falloc->waitq &&
+ vmf->pgoff >= shmem_falloc->start &&
+ vmf->pgoff < shmem_falloc->next) {
+ wait_queue_head_t *shmem_falloc_waitq;
+ DEFINE_WAIT(shmem_fault_wait);
+
+ ret = VM_FAULT_NOPAGE;
+ if ((vmf->flags & FAULT_FLAG_ALLOW_RETRY) &&
+ !(vmf->flags & FAULT_FLAG_RETRY_NOWAIT)) {
+ /* It's polite to up mmap_sem if we can */
+ up_read(&vma->vm_mm->mmap_sem);
+ ret = VM_FAULT_RETRY;
+ }
+
+ shmem_falloc_waitq = shmem_falloc->waitq;
+ prepare_to_wait(shmem_falloc_waitq, &shmem_fault_wait,
+ TASK_UNINTERRUPTIBLE);
+ spin_unlock(&inode->i_lock);
+ schedule();
+
+ /*
+ * shmem_falloc_waitq points into the shmem_fallocate()
+ * stack of the hole-punching task: shmem_falloc_waitq
+ * is usually invalid by the time we reach here, but
+ * finish_wait() does not dereference it in that case;
+ * though i_lock needed lest racing with wake_up_all().
+ */
+ spin_lock(&inode->i_lock);
+ finish_wait(shmem_falloc_waitq, &shmem_fault_wait);
+ spin_unlock(&inode->i_lock);
+ return ret;
+ }
+ spin_unlock(&inode->i_lock);
+ }
+
error = shmem_getpage(inode, vmf->pgoff, &vmf->page, SGP_CACHE, &ret);
if (error)
return ((error == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS);
@@ -1820,12 +1886,25 @@ static long shmem_fallocate(struct file *file, int mode, loff_t offset,
struct address_space *mapping = file->f_mapping;
loff_t unmap_start = round_up(offset, PAGE_SIZE);
loff_t unmap_end = round_down(offset + len, PAGE_SIZE) - 1;
+ DECLARE_WAIT_QUEUE_HEAD_ONSTACK(shmem_falloc_waitq);
+
+ shmem_falloc.waitq = &shmem_falloc_waitq;
+ shmem_falloc.start = unmap_start >> PAGE_SHIFT;
+ shmem_falloc.next = (unmap_end + 1) >> PAGE_SHIFT;
+ spin_lock(&inode->i_lock);
+ inode->i_private = &shmem_falloc;
+ spin_unlock(&inode->i_lock);
if ((u64)unmap_end > (u64)unmap_start)
unmap_mapping_range(mapping, unmap_start,
1 + unmap_end - unmap_start, 0);
shmem_truncate_range(inode, offset, offset + len - 1);
/* No need to unmap again: hole-punching leaves COWed pages */
+
+ spin_lock(&inode->i_lock);
+ inode->i_private = NULL;
+ wake_up_all(&shmem_falloc_waitq);
+ spin_unlock(&inode->i_lock);
error = 0;
goto out;
}
@@ -1843,6 +1922,7 @@ static long shmem_fallocate(struct file *file, int mode, loff_t offset,
goto out;
}
+ shmem_falloc.waitq = NULL;
shmem_falloc.start = start;
shmem_falloc.next = start;
shmem_falloc.nr_falloced = 0;
diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c
index 26dbd9a..fbd6bbf 100644
--- a/net/l2tp/l2tp_ppp.c
+++ b/net/l2tp/l2tp_ppp.c
@@ -1404,7 +1404,7 @@ static int pppol2tp_setsockopt(struct socket *sock, int level, int optname,
int err;
if (level != SOL_PPPOL2TP)
- return udp_prot.setsockopt(sk, level, optname, optval, optlen);
+ return -EINVAL;
if (optlen < sizeof(int))
return -EINVAL;
@@ -1530,7 +1530,7 @@ static int pppol2tp_getsockopt(struct socket *sock, int level, int optname,
struct pppol2tp_session *ps;
if (level != SOL_PPPOL2TP)
- return udp_prot.getsockopt(sk, level, optname, optval, optlen);
+ return -EINVAL;
if (get_user(len, optlen))
return -EFAULT;
diff --git a/net/sctp/associola.c b/net/sctp/associola.c
index 67c6823..c5cd799 100644
--- a/net/sctp/associola.c
+++ b/net/sctp/associola.c
@@ -396,7 +396,7 @@ void sctp_association_free(struct sctp_association *asoc)
/* Only real associations count against the endpoint, so
* don't bother for if this is a temporary association.
*/
- if (!asoc->temp) {
+ if (!list_empty(&asoc->asocs)) {
list_del(&asoc->asocs);
/* Decrement the backlog value for a TCP-style listening
--
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