| Message ID | 20211013171606.25197-1-bostroesser@gmail.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | scsi: target: tcmu: allocate zeroed pages for data area | expand |
Bodo, > Tcmu populates the data area (used for communication with userspace) > with pages that are allocated by calling alloc_page(GFP_NOIO). > Therefore previous content of the allocated pages is exposed to user > space. Avoid this by adding __GFP_ZERO flag. Applied to 5.16/scsi-staging, thanks!
On Wed, 13 Oct 2021 19:16:06 +0200, Bodo Stroesser wrote: > Tcmu populates the data area (used for communication with > userspace) with pages that are allocated by calling > alloc_page(GFP_NOIO). > Therefore previous content of the allocated pages is exposed > to user space. Avoid this by adding __GFP_ZERO flag. > > Zeroing the pages does (nearly) not affect tcmu throughput, > because allocated pages are re-used for the data transfers of > later SCSI cmds. > > [...] Applied to 5.16/scsi-queue, thanks! [1/1] scsi: target: tcmu: allocate zeroed pages for data area https://git.kernel.org/mkp/scsi/c/1d2ac7b69d6a
diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c index dc220fad06fa..a19e53877b0b 100644 --- a/drivers/target/target_core_user.c +++ b/drivers/target/target_core_user.c @@ -5,6 +5,7 @@ * Copyright (C) 2015 Arrikto, Inc. * Copyright (C) 2017 Chinamobile, Inc. */ +#include <linux/delay.h> #include <linux/spinlock.h> #include <linux/module.h> @@ -523,8 +524,8 @@ static inline int tcmu_get_empty_block(struct tcmu_dev *udev, rcu_read_unlock(); for (i = cnt; i < page_cnt; i++) { - /* try to get new page from the mm */ - page = alloc_page(GFP_NOIO); + /* try to get new zeroed page from the mm */ + page = alloc_page(GFP_NOIO | __GFP_ZERO); if (!page) break;
Tcmu populates the data area (used for communication with userspace) with pages that are allocated by calling alloc_page(GFP_NOIO). Therefore previous content of the allocated pages is exposed to user space. Avoid this by adding __GFP_ZERO flag. Zeroing the pages does (nearly) not affect tcmu throughput, because allocated pages are re-used for the data transfers of later SCSI cmds. Signed-off-by: Bodo Stroesser <bostroesser@gmail.com> --- drivers/target/target_core_user.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)