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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] Fixes to the xenoprofile Linux driver.
# HG changeset patch
# User kaf24@xxxxxxxxxxxxxxxxxxxx
# Node ID 3dca5b4add2be8b6da2052aeddffc497920b9ce1
# Parent c20e766a1f725013b8f7409649291c1267fa8be6
Fixes to the xenoprofile Linux driver.
The active_domains code has race conditions:
* oprofile_set_active() calls set_active() method without holding
start_sem. This is clearly wrong, as xenoprof_set_active() makes
several hypercalls. oprofile_start(), for instance, could run in
the middle of xenoprof_set_active().
* adomain_write(), adomain_read() and xenoprof_set_active() access
global active_domains[] and adomains without synchronization. I
went for a simple, obvious fix and created another mutex. Instead,
one could move the shared data into oprof.c and protect it with
start_sem, but that's more invasive.
Also clean up the code dealing with /dev/oprofile/active_domains:
* Use parameters instead of global variables to pass domain ids
around. Give those globals internal linkage.
* Allocate buffers dynamically to conserve stack space.
* Treat writes with size zero exactly like a write containing no
domain id. Before, zero-sized write was ignored, which is not the
same.
* Parse domain ids as unsigned numbers. Before, the first one was
parsed as signed number.
Because ispunct()-punctuation is ignored between domain ids, signs
are still silently ignored except for the first number. Hmm.
* Make parser accept whitespace as domain separator, because that's
what you get when reading the file.
* EINVAL on domain ids overflowing domid_t. Before, they were
silently truncated.
* EINVAL on too many domain ids. Before, the excess ones were
silently ignored.
* Reset active domains on failure halfway through setting them.
* Fix potential buffer overflow in adomain_read(). Couldn't really
happen because buffer was sufficient for current value of
MAX_OPROF_DOMAINS.
Signed-off-by: Markus Armbruster <armbru@xxxxxxxxxx>
---
linux-2.6-xen-sparse/arch/i386/oprofile/xenoprof.c | 13 ++++-
patches/linux-2.6.16.13/xenoprof-generic.patch | 46 ---------------------
2 files changed, 12 insertions(+), 47 deletions(-)
diff -r c20e766a1f72 -r 3dca5b4add2b
linux-2.6-xen-sparse/arch/i386/oprofile/xenoprof.c
--- a/linux-2.6-xen-sparse/arch/i386/oprofile/xenoprof.c Tue May 16
13:46:57 2006 +0100
+++ b/linux-2.6-xen-sparse/arch/i386/oprofile/xenoprof.c Tue May 16
14:07:56 2006 +0100
@@ -289,9 +289,13 @@ static int xenoprof_set_active(int * act
for (i=0; i<adomains; i++) {
domid = active_domains[i];
+ if (domid != active_domains[i]) {
+ ret = -EINVAL;
+ goto out;
+ }
ret = HYPERVISOR_xenoprof_op(XENOPROF_set_active, &domid);
if (ret)
- return (ret);
+ goto out;
if (active_domains[i] == 0)
set_dom0 = 1;
}
@@ -300,8 +304,11 @@ static int xenoprof_set_active(int * act
domid = 0;
ret = HYPERVISOR_xenoprof_op(XENOPROF_set_active, &domid);
}
-
- active_defined = 1;
+
+out:
+ if (ret)
+ HYPERVISOR_xenoprof_op(XENOPROF_reset_active_list, NULL);
+ active_defined = !ret;
return ret;
}
diff -r c20e766a1f72 -r 3dca5b4add2b
patches/linux-2.6.16.13/xenoprof-generic.patch
--- a/patches/linux-2.6.16.13/xenoprof-generic.patch Tue May 16 13:46:57
2006 +0100
+++ b/patches/linux-2.6.16.13/xenoprof-generic.patch Tue May 16 14:07:56
2006 +0100
@@ -225,19 +225,21 @@ diff -pruN ../pristine-linux-2.6.16.13/d
struct oprofile_operations oprofile_ops;
unsigned long oprofile_started;
-@@ -33,6 +37,17 @@ static DECLARE_MUTEX(start_sem);
+@@ -33,6 +37,19 @@ static DECLARE_MUTEX(start_sem);
*/
static int timer = 0;
-+extern unsigned int adomains;
-+extern int active_domains[MAX_OPROF_DOMAINS];
-+
-+int oprofile_set_active(void)
++int oprofile_set_active(int active_domains[], unsigned int adomains)
+{
-+ if (oprofile_ops.set_active)
-+ return oprofile_ops.set_active(active_domains, adomains);
-+
-+ return -EINVAL;
++ int err;
++
++ if (!oprofile_ops.set_active)
++ return -EINVAL;
++
++ down(&start_sem);
++ err = oprofile_ops.set_active(active_domains, adomains);
++ up(&start_sem);
++ return err;
+}
+
int oprofile_setup(void)
@@ -251,7 +253,7 @@ diff -pruN ../pristine-linux-2.6.16.13/d
int oprofile_set_backtrace(unsigned long depth);
+
-+int oprofile_set_active(void);
++int oprofile_set_active(int active_domains[], unsigned int adomains);
#endif /* OPROF_H */
diff -pruN ../pristine-linux-2.6.16.13/drivers/oprofile/oprofile_files.c
./drivers/oprofile/oprofile_files.c
@@ -280,7 +282,7 @@ diff -pruN ../pristine-linux-2.6.16.13/d
unsigned long fs_buffer_size = 131072;
unsigned long fs_cpu_buffer_size = 8192;
unsigned long fs_buffer_watershed = 32768; /* FIXME: tune */
-@@ -117,11 +123,79 @@ static ssize_t dump_write(struct file *
+@@ -117,11 +123,108 @@ static ssize_t dump_write(struct file *
static struct file_operations dump_fops = {
.write = dump_write,
};
@@ -288,63 +290,92 @@ diff -pruN ../pristine-linux-2.6.16.13/d
+
+#define TMPBUFSIZE 512
+
-+unsigned int adomains = 0;
-+long active_domains[MAX_OPROF_DOMAINS];
++static unsigned int adomains = 0;
++static int active_domains[MAX_OPROF_DOMAINS + 1];
++static DEFINE_MUTEX(adom_mutex);
+
+static ssize_t adomain_write(struct file * file, char const __user * buf,
+ size_t count, loff_t * offset)
+{
-+ char tmpbuf[TMPBUFSIZE];
-+ char * startp = tmpbuf;
-+ char * endp = tmpbuf;
++ char *tmpbuf;
++ char *startp, *endp;
+ int i;
+ unsigned long val;
++ ssize_t retval = count;
+
+ if (*offset)
+ return -EINVAL;
-+ if (!count)
-+ return 0;
+ if (count > TMPBUFSIZE - 1)
+ return -EINVAL;
+
-+ memset(tmpbuf, 0x0, TMPBUFSIZE);
-+
-+ if (copy_from_user(tmpbuf, buf, count))
++ if (!(tmpbuf = kmalloc(TMPBUFSIZE, GFP_KERNEL)))
++ return -ENOMEM;
++
++ if (copy_from_user(tmpbuf, buf, count)) {
++ kfree(tmpbuf);
+ return -EFAULT;
-+
-+ for (i = 0; i < MAX_OPROF_DOMAINS; i++)
-+ active_domains[i] = -1;
-+ adomains = 0;
-+
-+ while (1) {
-+ val = simple_strtol(startp, &endp, 0);
++ }
++ tmpbuf[count] = 0;
++
++ mutex_lock(&adom_mutex);
++
++ startp = tmpbuf;
++ /* Parse one more than MAX_OPROF_DOMAINS, for easy error checking */
++ for (i = 0; i <= MAX_OPROF_DOMAINS; i++) {
++ val = simple_strtoul(startp, &endp, 0);
+ if (endp == startp)
+ break;
-+ while (ispunct(*endp))
++ while (ispunct(*endp) || isspace(*endp))
+ endp++;
-+ active_domains[adomains++] = val;
-+ if (adomains >= MAX_OPROF_DOMAINS)
-+ break;
++ active_domains[i] = val;
++ if (active_domains[i] != val)
++ /* Overflow, force error below */
++ i = MAX_OPROF_DOMAINS + 1;
+ startp = endp;
+ }
-+ if (oprofile_set_active())
-+ return -EINVAL;
-+ return count;
++ /* Force error on trailing junk */
++ adomains = *startp ? MAX_OPROF_DOMAINS + 1 : i;
++
++ kfree(tmpbuf);
++
++ if (adomains > MAX_OPROF_DOMAINS
++ || oprofile_set_active(active_domains, adomains)) {
++ adomains = 0;
++ retval = -EINVAL;
++ }
++
++ mutex_unlock(&adom_mutex);
++ return retval;
+}
+
+static ssize_t adomain_read(struct file * file, char __user * buf,
+ size_t count, loff_t * offset)
+{
-+ char tmpbuf[TMPBUFSIZE];
-+ size_t len = 0;
++ char * tmpbuf;
++ size_t len;
+ int i;
-+ /* This is all screwed up if we run out of space */
-+ for (i = 0; i < adomains; i++)
-+ len += snprintf(tmpbuf + len, TMPBUFSIZE - len,
-+ "%u ", (unsigned int)active_domains[i]);
-+ len += snprintf(tmpbuf + len, TMPBUFSIZE - len, "\n");
-+ return simple_read_from_buffer((void __user *)buf, count,
-+ offset, tmpbuf, len);
++ ssize_t retval;
++
++ if (!(tmpbuf = kmalloc(TMPBUFSIZE, GFP_KERNEL)))
++ return -ENOMEM;
++
++ mutex_lock(&adom_mutex);
++
++ len = 0;
++ for (i = 0; i < adomains; i++)
++ len += snprintf(tmpbuf + len,
++ len < TMPBUFSIZE ? TMPBUFSIZE - len : 0,
++ "%u ", active_domains[i]);
++ WARN_ON(len > TMPBUFSIZE);
++ if (len != 0 && len <= TMPBUFSIZE)
++ tmpbuf[len-1] = '\n';
++
++ mutex_unlock(&adom_mutex);
++
++ retval = simple_read_from_buffer(buf, count, offset, tmpbuf, len);
++
++ kfree(tmpbuf);
++ return retval;
+}
+
+
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