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authorTony Luck <tony.luck@intel.com>2014-06-04 16:11:01 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-06-30 20:09:42 -0700
commit15e09f82416374a28bcea21315f600df344f9a6c (patch)
tree15f506b137e7e87cf0dd8edb62b4192da53c4a5c /mm
parent4451dd21497254e6f9d28a528bad70cf31a1db91 (diff)
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mm/memory-failure.c: don't let collect_procs() skip over processes for MF_ACTION_REQUIRED
commit 74614de17db6fb472370c426d4f934d8d616edf2 upstream. When Linux sees an "action optional" machine check (where h/w has reported an error that is not in the current execution path) we generally do not want to signal a process, since most processes do not have a SIGBUS handler - we'd just prematurely terminate the process for a problem that they might never actually see. task_early_kill() decides whether to consider a process - and it checks whether this specific process has been marked for early signals with "prctl", or if the system administrator has requested early signals for all processes using /proc/sys/vm/memory_failure_early_kill. But for MF_ACTION_REQUIRED case we must not defer. The error is in the execution path of the current thread so we must send the SIGBUS immediatley. Fix by passing a flag argument through collect_procs*() to task_early_kill() so it knows whether we can defer or must take action. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Borislav Petkov <bp@suse.de> Cc: Chen Gong <gong.chen@linux.jf.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/memory-failure.c21
1 files changed, 12 insertions, 9 deletions
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index bf1b075ff6c..603f1fa1b7a 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -382,10 +382,12 @@ static void kill_procs(struct list_head *to_kill, int forcekill, int trapno,
}
}
-static int task_early_kill(struct task_struct *tsk)
+static int task_early_kill(struct task_struct *tsk, int force_early)
{
if (!tsk->mm)
return 0;
+ if (force_early)
+ return 1;
if (tsk->flags & PF_MCE_PROCESS)
return !!(tsk->flags & PF_MCE_EARLY);
return sysctl_memory_failure_early_kill;
@@ -395,7 +397,7 @@ static int task_early_kill(struct task_struct *tsk)
* Collect processes when the error hit an anonymous page.
*/
static void collect_procs_anon(struct page *page, struct list_head *to_kill,
- struct to_kill **tkc)
+ struct to_kill **tkc, int force_early)
{
struct vm_area_struct *vma;
struct task_struct *tsk;
@@ -411,7 +413,7 @@ static void collect_procs_anon(struct page *page, struct list_head *to_kill,
for_each_process (tsk) {
struct anon_vma_chain *vmac;
- if (!task_early_kill(tsk))
+ if (!task_early_kill(tsk, force_early))
continue;
anon_vma_interval_tree_foreach(vmac, &av->rb_root,
pgoff, pgoff) {
@@ -430,7 +432,7 @@ static void collect_procs_anon(struct page *page, struct list_head *to_kill,
* Collect processes when the error hit a file mapped page.
*/
static void collect_procs_file(struct page *page, struct list_head *to_kill,
- struct to_kill **tkc)
+ struct to_kill **tkc, int force_early)
{
struct vm_area_struct *vma;
struct task_struct *tsk;
@@ -441,7 +443,7 @@ static void collect_procs_file(struct page *page, struct list_head *to_kill,
for_each_process(tsk) {
pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
- if (!task_early_kill(tsk))
+ if (!task_early_kill(tsk, force_early))
continue;
vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff,
@@ -467,7 +469,8 @@ static void collect_procs_file(struct page *page, struct list_head *to_kill,
* First preallocate one tokill structure outside the spin locks,
* so that we can kill at least one process reasonably reliable.
*/
-static void collect_procs(struct page *page, struct list_head *tokill)
+static void collect_procs(struct page *page, struct list_head *tokill,
+ int force_early)
{
struct to_kill *tk;
@@ -478,9 +481,9 @@ static void collect_procs(struct page *page, struct list_head *tokill)
if (!tk)
return;
if (PageAnon(page))
- collect_procs_anon(page, tokill, &tk);
+ collect_procs_anon(page, tokill, &tk, force_early);
else
- collect_procs_file(page, tokill, &tk);
+ collect_procs_file(page, tokill, &tk, force_early);
kfree(tk);
}
@@ -965,7 +968,7 @@ static int hwpoison_user_mappings(struct page *p, unsigned long pfn,
* there's nothing that can be done.
*/
if (kill)
- collect_procs(ppage, &tokill);
+ collect_procs(ppage, &tokill, flags & MF_ACTION_REQUIRED);
ret = try_to_unmap(ppage, ttu);
if (ret != SWAP_SUCCESS)