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| author | Mikhail Zaslonko <zaslonko@linux.ibm.com> | 2019-02-01 14:20:38 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-03-13 14:03:18 -0700 |
| commit | d83382c6c3c751867dbbadd0d4a2740ba028dd85 (patch) | |
| tree | 2d707088726628b510201ed0b4b53f448973ee58 /mm/memory_hotplug.c | |
| parent | 659052d1f16e0c3af60a371fa0147c007eba5a97 (diff) | |
| download | linux-stable-d83382c6c3c751867dbbadd0d4a2740ba028dd85.tar.gz linux-stable-d83382c6c3c751867dbbadd0d4a2740ba028dd85.tar.bz2 linux-stable-d83382c6c3c751867dbbadd0d4a2740ba028dd85.zip | |
mm, memory_hotplug: test_pages_in_a_zone do not pass the end of zone
[ Upstream commit 24feb47c5fa5b825efb0151f28906dfdad027e61 ]
If memory end is not aligned with the sparse memory section boundary,
the mapping of such a section is only partly initialized. This may lead
to VM_BUG_ON due to uninitialized struct pages access from
test_pages_in_a_zone() function triggered by memory_hotplug sysfs
handlers.
Here are the the panic examples:
CONFIG_DEBUG_VM_PGFLAGS=y
kernel parameter mem=2050M
--------------------------
page:000003d082008000 is uninitialized and poisoned
page dumped because: VM_BUG_ON_PAGE(PagePoisoned(p))
Call Trace:
test_pages_in_a_zone+0xde/0x160
show_valid_zones+0x5c/0x190
dev_attr_show+0x34/0x70
sysfs_kf_seq_show+0xc8/0x148
seq_read+0x204/0x480
__vfs_read+0x32/0x178
vfs_read+0x82/0x138
ksys_read+0x5a/0xb0
system_call+0xdc/0x2d8
Last Breaking-Event-Address:
test_pages_in_a_zone+0xde/0x160
Kernel panic - not syncing: Fatal exception: panic_on_oops
Fix this by checking whether the pfn to check is within the zone.
[mhocko@suse.com: separated this change from http://lkml.kernel.org/r/20181105150401.97287-2-zaslonko@linux.ibm.com]
Link: http://lkml.kernel.org/r/20190128144506.15603-3-mhocko@kernel.org
[mhocko@suse.com: separated this change from
http://lkml.kernel.org/r/20181105150401.97287-2-zaslonko@linux.ibm.com]
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Mikhail Zaslonko <zaslonko@linux.ibm.com>
Tested-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Tested-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'mm/memory_hotplug.c')
| -rw-r--r-- | mm/memory_hotplug.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 39db89f3df65..c9d3a49bd4e2 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1297,6 +1297,9 @@ int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn, i++; if (i == MAX_ORDER_NR_PAGES || pfn + i >= end_pfn) continue; + /* Check if we got outside of the zone */ + if (zone && !zone_spans_pfn(zone, pfn + i)) + return 0; page = pfn_to_page(pfn + i); if (zone && page_zone(page) != zone) return 0; |