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authorAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>2015-11-06 05:50:51 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2015-11-06 06:34:48 +0300
commitfc5aeeaf593278f07ffa4d97296e27423ecae867 (patch)
tree17b6521e9f9ba2d43d6d0b4d416d5a599e561980 /mm
parentf2377d4eaab2aabe1938b3974b5b94f5ba4c7ead (diff)
downloadlinux-fc5aeeaf593278f07ffa4d97296e27423ecae867.tar.xz
mm/kasan: prevent deadlock in kasan reporting
When we end up calling kasan_report in real mode, our shadow mapping for the spinlock variable will show poisoned. This will result in us calling kasan_report_error with lock_report spin lock held. To prevent this disable kasan reporting when we are priting error w.r.t kasan. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Reviewed-by: Andrey Ryabinin <ryabinin.a.a@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/kasan/report.c12
1 files changed, 10 insertions, 2 deletions
diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index c5367089703c..7833f074ede8 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -173,12 +173,10 @@ static void print_shadow_for_address(const void *addr)
* function, because generic functions may try to
* access kasan mapping for the passed address.
*/
- kasan_disable_current();
memcpy(shadow_buf, shadow_row, SHADOW_BYTES_PER_ROW);
print_hex_dump(KERN_ERR, buffer,
DUMP_PREFIX_NONE, SHADOW_BYTES_PER_ROW, 1,
shadow_buf, SHADOW_BYTES_PER_ROW, 0);
- kasan_enable_current();
if (row_is_guilty(shadow_row, shadow))
pr_err("%*c\n",
@@ -195,6 +193,10 @@ void kasan_report_error(struct kasan_access_info *info)
{
unsigned long flags;
+ /*
+ * Make sure we don't end up in loop.
+ */
+ kasan_disable_current();
spin_lock_irqsave(&report_lock, flags);
pr_err("================================="
"=================================\n");
@@ -204,12 +206,17 @@ void kasan_report_error(struct kasan_access_info *info)
pr_err("================================="
"=================================\n");
spin_unlock_irqrestore(&report_lock, flags);
+ kasan_enable_current();
}
void kasan_report_user_access(struct kasan_access_info *info)
{
unsigned long flags;
+ /*
+ * Make sure we don't end up in loop.
+ */
+ kasan_disable_current();
spin_lock_irqsave(&report_lock, flags);
pr_err("================================="
"=================================\n");
@@ -222,6 +229,7 @@ void kasan_report_user_access(struct kasan_access_info *info)
pr_err("================================="
"=================================\n");
spin_unlock_irqrestore(&report_lock, flags);
+ kasan_enable_current();
}
void kasan_report(unsigned long addr, size_t size,