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ia64/err-inject: Use get_user_pages_fast() 

[ Upstream commit 69c907022a ]

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>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
pull/10/head
Davidlohr Bueso 2018-01-22 09:21:37 -08:00 committed by Greg Kroah-Hartman
parent d98ba4f456
commit 87bcb00aa9
1 changed files with 1 additions and 1 deletions
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arch/ia64/kernel/err_inject.c
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@ -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);