[PATCH 2/2] efivarfs: Don't return -EINTR when rate-limiting reads

From: Tony Luck
Date: Thu May 28 2020 - 15:49:25 EST


Applications that read EFI variables may see a return
value of -EINTR if they exceed the rate limit and a
signal delivery is attempted while the process is sleeping.

This is quite surprising to the application, which probably
doesn't have code to handle it.

Change the interruptible sleep to a non-interruptible one.

Reported-by: Lennart Poettering <mzxreary@xxxxxxxxxxx>
Signed-off-by: Tony Luck <tony.luck@xxxxxxxxx>
---
fs/efivarfs/file.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/fs/efivarfs/file.c b/fs/efivarfs/file.c
index 4b8bc4560d70..feaa5e182b7b 100644
--- a/fs/efivarfs/file.c
+++ b/fs/efivarfs/file.c
@@ -73,10 +73,8 @@ static ssize_t efivarfs_file_read(struct file *file, char __user *userbuf,
ssize_t size = 0;
int err;

- while (!__ratelimit(&file->f_cred->user->ratelimit)) {
- if (!msleep_interruptible(50))
- return -EINTR;
- }
+ while (!__ratelimit(&file->f_cred->user->ratelimit))
+ msleep(50);

err = efivar_entry_size(var, &datasize);

--
2.21.1