Attachment 115491 Details for Bug 90262 – systemd/master udev net_id PCIe config read patch

[patch] systemd/master udev net_id PCIe config read patch

systemd-udev-master.patch (text/plain), 2.08 KB, created by Jason S. McMullan on 2015-05-01 00:02:04 UTC

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Creator: Jason S. McMullan

Created: 2015-05-01 00:02:04 UTC

Size: 2.08 KB

patch

obsolete

>commit 4bad4a31c423faa4c5160652b57fd2e7cebfb38a
>Author: Jason S. McMullan <jason.mcmullan@gmail.com>
>Date:   Thu Apr 30 19:46:04 2015 -0400
>
>    udev/net_id: Only read the first 64 bytes of PCI config space
>    
>    The original code used fread(), which on some libc implementions
>    (ie glibc 2.17) would pre-read a full 4K (PAGE_SIZE) of the
>    PCI config space, when only 64 bytes were requested.
>    
>    I have recently come across PCIe hardware which responds with
>    Completion Timeouts when accesses above 256 bytes are attempted.
>    
>    This can cause server systems with GHES/AEPI support to cause
>    and immediate kernel panic due to the failed PCI transaction.
>    
>    This change replaces the buffered fread() with an explict
>    unbuffered read() of 64 bytes, which corrects this issue by
>    only reading the guaranteed first 64 bytes of PCIe config space.
>    
>    Signed-off-by: Jason S. McMullan <jason.mcmullan@gmail.com>
>
>diff --git a/src/udev/udev-builtin-net_id.c b/src/udev/udev-builtin-net_id.c
>index 78aef20..4489205 100644
>--- a/src/udev/udev-builtin-net_id.c
>+++ b/src/udev/udev-builtin-net_id.c
>@@ -91,6 +91,7 @@
> #include <stdlib.h>
> #include <stdarg.h>
> #include <unistd.h>
>+#include <fcntl.h>
> #include <string.h>
> #include <errno.h>
> #include <net/if.h>
>@@ -166,15 +167,15 @@ static int dev_pci_onboard(struct udev_device *dev, struct netnames *names) {
> 
> /* read the 256 bytes PCI configuration space to check the multi-function bit */
> static bool is_pci_multifunction(struct udev_device *dev) {
>-        _cleanup_fclose_ FILE *f = NULL;
>+        _cleanup_close_ int fd = -1;
>         const char *filename;
>         uint8_t config[64];
> 
>         filename = strjoina(udev_device_get_syspath(dev), "/config");
>-        f = fopen(filename, "re");
>-        if (!f)
>+        fd = open(filename, O_RDONLY | O_CLOEXEC);
>+        if (fd < 0)
>                 return false;
>-        if (fread(&config, sizeof(config), 1, f) != 1)
>+        if (read(fd, &config, sizeof(config)) != sizeof(config))
>                 return false;
> 
>         /* bit 0-6 header type, bit 7 multi/single function device */

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