The patch titled
Subject: ia64/err-inject: use get_user_pages_fast()
has been added to the -mm tree. Its filename is
ia64-err-inject-use-get_user_pages_fast.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/ia64-err-inject-use-get_user_pages_fast.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/ia64-err-inject-use-get_user_pages_fast.patch
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------------------------------------------------------
From: Davidlohr Bueso <dave@xxxxxxxxxxxx>
Subject: ia64/err-inject: use get_user_pages_fast()
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.
Link: http://lkml.kernel.org/r/20180122172137.26849-1-dave@xxxxxxxxxxxx
Signed-off-by: Davidlohr Bueso <dbueso@xxxxxxx>
Cc: Tony Luck <tony.luck@xxxxxxxxx>
Cc: Fenghua Yu <fenghua.yu@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/ia64/kernel/err_inject.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff -puN arch/ia64/kernel/err_inject.c~ia64-err-inject-use-get_user_pages_fast arch/ia64/kernel/err_inject.c
--- a/arch/ia64/kernel/err_inject.c~ia64-err-inject-use-get_user_pages_fast
+++ a/arch/ia64/kernel/err_inject.c
@@ -142,7 +142,7 @@ store_virtual_to_phys(struct device *dev
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);
_
Patches currently in -mm which might be from dave@xxxxxxxxxxxx are
ia64-err-inject-use-get_user_pages_fast.patch
ipc-shm-introduce-shmctlshm_stat_any.patch
ipc-sem-introduce-semctlsem_stat_any.patch
ipc-msg-introduce-msgctlmsg_stat_any.patch
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