Commit fc5aeeaf authored by Aneesh Kumar K.V's avatar Aneesh Kumar K.V Committed by Linus Torvalds

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: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Reviewed-by: default avatarAndrey Ryabinin <ryabinin.a.a@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f2377d4e
......@@ -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,
......
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