From: Tony Luck
mainline inclusion
from mainline-v5.13
commit 171936ddaf97e6f4e1264f4128bb5cf15691339c
category: bugfix
issue: #I4LRGQ
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
-------------------------------------------------
Patch series "mm,hwpoison: fix sending SIGBUS for Action Required MCE", v5.
I wrote this patchset to materialize what I think is the current
allowable solution mentioned by the previous discussion [1]. I simply
borrowed Tony's mutex patch and Aili's return code patch, then I queued
another one to find error virtual address in the best effort manner. I
know that this is not a perfect solution, but should work for some
typical case.
[1]: https://lore.kernel.org/linux-mm/20210331192540.2141052f@alex-virtual-machin...
This patch (of 2):
There can be races when multiple CPUs consume poison from the same page.
The first into memory_failure() atomically sets the HWPoison page flag
and begins hunting for tasks that map this page. Eventually it
invalidates those mappings and may send a SIGBUS to the affected tasks.
But while all that work is going on, other CPUs see a "success" return
code from memory_failure() and so they believe the error has been
handled and continue executing.
Fix by wrapping most of the internal parts of memory_failure() in a
mutex.
[akpm@linux-foundation.org: make mf_mutex local to memory_failure()]
Link: https://lkml.kernel.org/r/20210521030156.2612074-1-nao.horiguchi@gmail.com
Link: https://lkml.kernel.org/r/20210521030156.2612074-2-nao.horiguchi@gmail.com
Signed-off-by: Tony Luck
Signed-off-by: Naoya Horiguchi
Reviewed-by: Borislav Petkov
Reviewed-by: Oscar Salvador
Cc: Aili Yao
Cc: Andy Lutomirski
Cc: Borislav Petkov
Cc: David Hildenbrand
Cc: Jue Wang
Cc:
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
Conflicts:
mm/memory-failure.c
Signed-off-by: Nanyong Sun
Reviewed-by: Chen Wandun
Signed-off-by: Chen Jun
Signed-off-by: Zheng Zengkai
Signed-off-by: Yu Changchun
---
mm/memory-failure.c | 37 +++++++++++++++++++++++--------------
1 file changed, 23 insertions(+), 14 deletions(-)
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index d00d1b2e97da..8df59bb777a7 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1329,8 +1329,9 @@ int memory_failure(unsigned long pfn, int flags)
struct page *hpage;
struct page *orig_head;
struct dev_pagemap *pgmap;
- int res;
+ int res = 0;
unsigned long page_flags;
+ static DEFINE_MUTEX(mf_mutex);
if (!sysctl_memory_failure_recovery)
panic("Memory failure on page %lx", pfn);
@@ -1348,12 +1349,17 @@ int memory_failure(unsigned long pfn, int flags)
return -ENXIO;
}
- if (PageHuge(p))
- return memory_failure_hugetlb(pfn, flags);
+ mutex_lock(&mf_mutex);
+
+ if (PageHuge(p)) {
+ res = memory_failure_hugetlb(pfn, flags);
+ goto unlock_mutex;
+ }
+
if (TestSetPageHWPoison(p)) {
pr_err("Memory failure: %#lx: already hardware poisoned\n",
pfn);
- return 0;
+ goto unlock_mutex;
}
orig_head = hpage = compound_head(p);
@@ -1373,17 +1379,18 @@ int memory_failure(unsigned long pfn, int flags)
if (!(flags & MF_COUNT_INCREASED) && !get_hwpoison_page(p)) {
if (is_free_buddy_page(p)) {
action_result(pfn, MF_MSG_BUDDY, MF_DELAYED);
- return 0;
} else {
action_result(pfn, MF_MSG_KERNEL_HIGH_ORDER, MF_IGNORED);
- return -EBUSY;
+ res = -EBUSY;
}
+ goto unlock_mutex;
}
if (PageTransHuge(hpage)) {
if (try_to_split_thp_page(p, "Memory Failure") < 0) {
action_result(pfn, MF_MSG_UNSPLIT_THP, MF_IGNORED);
- return -EBUSY;
+ res = -EBUSY;
+ goto unlock_mutex;
}
VM_BUG_ON_PAGE(!page_count(p), p);
}
@@ -1403,7 +1410,7 @@ int memory_failure(unsigned long pfn, int flags)
action_result(pfn, MF_MSG_BUDDY, MF_DELAYED);
else
action_result(pfn, MF_MSG_BUDDY_2ND, MF_DELAYED);
- return 0;
+ goto unlock_mutex;
}
lock_page(p);
@@ -1415,7 +1422,7 @@ int memory_failure(unsigned long pfn, int flags)
if (PageCompound(p) && compound_head(p) != orig_head) {
action_result(pfn, MF_MSG_DIFFERENT_COMPOUND, MF_IGNORED);
res = -EBUSY;
- goto out;
+ goto unlock_page;
}
/*
@@ -1435,14 +1442,14 @@ int memory_failure(unsigned long pfn, int flags)
num_poisoned_pages_dec();
unlock_page(p);
put_page(p);
- return 0;
+ goto unlock_mutex;
}
if (hwpoison_filter(p)) {
if (TestClearPageHWPoison(p))
num_poisoned_pages_dec();
unlock_page(p);
put_page(p);
- return 0;
+ goto unlock_mutex;
}
/*
@@ -1466,7 +1473,7 @@ int memory_failure(unsigned long pfn, int flags)
if (!hwpoison_user_mappings(p, pfn, flags, &p)) {
action_result(pfn, MF_MSG_UNMAP_FAILED, MF_IGNORED);
res = -EBUSY;
- goto out;
+ goto unlock_page;
}
/*
@@ -1475,13 +1482,15 @@ int memory_failure(unsigned long pfn, int flags)
if (PageLRU(p) && !PageSwapCache(p) && p->mapping == NULL) {
action_result(pfn, MF_MSG_TRUNCATED_LRU, MF_IGNORED);
res = -EBUSY;
- goto out;
+ goto unlock_page;
}
identify_page_state:
res = identify_page_state(pfn, p, page_flags);
-out:
+unlock_page:
unlock_page(p);
+unlock_mutex:
+ mutex_unlock(&mf_mutex);
return res;
}
EXPORT_SYMBOL_GPL(memory_failure);
--
2.25.1
