[dpdk-dev] mem: Warn once if /proc/self/pagemap is unreadable
Commit Message
Newer kernels make this unreadable for security reasons for non-roots.
Running the application will then fill the logs with
rte_mem_virt2phy: cannot open /proc/self/pagemap
messages.
However, there are cases when DPDK is and should be run as non-root,
without the need for virtual-to-physical address translations: a
typical example is when working with PCAP input/output. This patch
adds a start-time check for /proc/self/pagemap readability, and
directly returns an error code from rte_mem_virt2phy().
This way, there is only a one-time warning at startup instead of
constant warnings all the time.
Signed-off-by: Simon Kagstrom <simon.kagstrom@netinsight.net>
Signed-off-by: Johan Faltstrom <johan.faltstrom@netinsight.net>
---
lib/librte_eal/linuxapp/eal/eal_memory.c | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)
Comments
On 2015-06-23 12:39, Simon Kagstrom wrote:
> Newer kernels make this unreadable for security reasons for non-roots.
> Running the application will then fill the logs with
>
> rte_mem_virt2phy: cannot open /proc/self/pagemap
>
> messages.
I found a bug with the patch, so please disregard it for a while.
Sorry about that!
// Simon
@@ -111,6 +111,8 @@
static uint64_t baseaddr_offset;
+static unsigned proc_pagemap_readable;
+
#define RANDOMIZE_VA_SPACE_FILE "/proc/sys/kernel/randomize_va_space"
/* Lock page in physical memory and prevent from swapping. */
@@ -135,6 +137,10 @@ rte_mem_virt2phy(const void *virtaddr)
int page_size;
off_t offset;
+ /* Cannot parse /proc/self/pagemap, no need to log errors everywhere */
+ if (!proc_pagemap_readable)
+ return RTE_BAD_PHYS_ADDR;
+
/* standard page size */
page_size = getpagesize();
@@ -1546,6 +1552,18 @@ rte_eal_memdevice_init(void)
return 0;
}
+static int
+test_proc_pagemap_readable(void)
+{
+ int fd = open("/proc/self/pagemap", O_RDONLY);
+
+ if (fd < 0)
+ return 0;
+ /* Is readable */
+ close(fd);
+
+ return 1;
+}
/* init memory subsystem */
int
@@ -1561,5 +1579,11 @@ rte_eal_memory_init(void)
if (internal_config.no_shconf == 0 && rte_eal_memdevice_init() < 0)
return -1;
+ proc_pagemap_readable = test_proc_pagemap_readable();
+ if (!proc_pagemap_readable)
+ RTE_LOG(ERR, EAL,
+ "Cannot open /proc/self/pagemap: %s. virt2phys address translation will not work\n",
+ strerror(errno));
+
return 0;
}