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Subject[PATCH] ia64/err-inject: Use get_user_pages_fast()
Date
At the point of sysfs callback, the call to gup is
done without mmap_sem (or any lock for that matter).
This is racy. As such, use the get_user_pages_fast()
alternative and safely avoid taking the lock, if possible.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
---
arch/ia64/kernel/err_inject.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/ia64/kernel/err_inject.c b/arch/ia64/kernel/err_inject.c
index 85bba43e7d5d..658a8e06a69b 100644
--- a/arch/ia64/kernel/err_inject.c
+++ b/arch/ia64/kernel/err_inject.c
@@ -142,7 +142,7 @@ store_virtual_to_phys(struct device *dev, struct device_attribute *attr,
u64 virt_addr=simple_strtoull(buf, NULL, 16);
int ret;

- ret = get_user_pages(virt_addr, 1, FOLL_WRITE, NULL, NULL);
+ ret = get_user_pages_fast(virt_addr, 1, FOLL_WRITE, NULL);
if (ret<=0) {
#ifdef ERR_INJ_DEBUG
printk("Virtual address %lx is not existing.\n",virt_addr);
--
2.13.6
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