The patch titled
markers: fix warnings
has been added to the -mm tree. Its filename is
markers-fix-warnings.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: markers: fix warnings
From: Dave Hansen <haveblue@xxxxxxxxxx>
kernel/marker.c: In function `marker_probe_unregister':
kernel/marker.c:355: warning: `probe_module' might be used uninitialized in this function
kernel/marker.c: In function `marker_probe_unregister_private_data':
kernel/marker.c:389: warning: `probe_module' might be used uninitialized in this function
kernel/marker.c:392: warning: `entry' might be used uninitialized in this function
It's due to gcc not detecting that the need_update condition is actually
constant, and will never call marker_update_probes() on an uninitialized
probe_module.
However, that need_update bit is all due to dropping the mutex before
calling marker_update_probes(). As far as I can tell, every call to
marker_update_probes() has this lock dropping behavior just before calling
it. So, let's just hold the locks over the marker_update_probes() and
document that it needs to have a lock taken instead.
This removes code overall.
marker_probe_unregister_private_data() also has a bit of a goto mess
that produces similar warnings. I'll look at it next.
Signed-off-by: Dave Hansen <haveblue@xxxxxxxxxx>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/marker.c | 34 +++++++++++-----------------------
1 file changed, 11 insertions(+), 23 deletions(-)
diff -puN kernel/marker.c~markers-fix-warnings kernel/marker.c
--- a/kernel/marker.c~markers-fix-warnings
+++ a/kernel/marker.c
@@ -288,12 +288,13 @@ void marker_update_probe_range(struct ma
* Issues a synchronize_sched() when no reference to the module passed
* as parameter is found in the probes so the probe module can be
* safely unloaded from now on.
+ *
+ * must hold markers_mutex
*/
-static void marker_update_probes(struct module *probe_module)
+static void __marker_update_probes(struct module *probe_module)
{
int refcount = 0;
- mutex_lock(&markers_mutex);
/* Core kernel markers */
marker_update_probe_range(__start___markers,
__stop___markers, probe_module, &refcount);
@@ -303,7 +304,6 @@ static void marker_update_probes(struct
synchronize_sched();
deferred_sync = 0;
}
- mutex_unlock(&markers_mutex);
}
/**
@@ -320,7 +320,7 @@ int marker_probe_register(const char *na
marker_probe_func *probe, void *private)
{
struct marker_entry *entry;
- int ret = 0, need_update = 0;
+ int ret = 0;
mutex_lock(&markers_mutex);
entry = get_marker(name);
@@ -335,11 +335,9 @@ int marker_probe_register(const char *na
ret = add_marker(name, format, probe, private);
if (ret)
goto end;
- need_update = 1;
+ __marker_update_probes(NULL);
end:
mutex_unlock(&markers_mutex);
- if (need_update)
- marker_update_probes(NULL);
return ret;
}
EXPORT_SYMBOL_GPL(marker_probe_register);
@@ -355,7 +353,6 @@ void *marker_probe_unregister(const char
struct module *probe_module;
struct marker_entry *entry;
void *private;
- int need_update = 0;
mutex_lock(&markers_mutex);
entry = get_marker(name);
@@ -368,11 +365,9 @@ void *marker_probe_unregister(const char
probe_module = __module_text_address((unsigned long)entry->probe);
private = remove_marker(name);
deferred_sync = 1;
- need_update = 1;
+ __marker_update_probes(probe_module);
end:
mutex_unlock(&markers_mutex);
- if (need_update)
- marker_update_probes(probe_module);
return private;
}
EXPORT_SYMBOL_GPL(marker_probe_unregister);
@@ -392,7 +387,6 @@ void *marker_probe_unregister_private_da
struct marker_entry *entry;
int found = 0;
unsigned int i;
- int need_update = 0;
mutex_lock(&markers_mutex);
for (i = 0; i < MARKER_TABLE_SIZE; i++) {
@@ -414,11 +408,9 @@ iter_end:
probe_module = __module_text_address((unsigned long)entry->probe);
private = remove_marker(entry->name);
deferred_sync = 1;
- need_update = 1;
+ __marker_update_probes(probe_module);
end:
mutex_unlock(&markers_mutex);
- if (need_update)
- marker_update_probes(probe_module);
return private;
}
EXPORT_SYMBOL_GPL(marker_probe_unregister_private_data);
@@ -434,7 +426,7 @@ EXPORT_SYMBOL_GPL(marker_probe_unregiste
int marker_arm(const char *name)
{
struct marker_entry *entry;
- int ret = 0, need_update = 0;
+ int ret = 0;
mutex_lock(&markers_mutex);
entry = get_marker(name);
@@ -447,11 +439,9 @@ int marker_arm(const char *name)
*/
if (entry->refcount++)
goto end;
- need_update = 1;
end:
+ __marker_update_probes(NULL);
mutex_unlock(&markers_mutex);
- if (need_update)
- marker_update_probes(NULL);
return ret;
}
EXPORT_SYMBOL_GPL(marker_arm);
@@ -467,7 +457,7 @@ EXPORT_SYMBOL_GPL(marker_arm);
int marker_disarm(const char *name)
{
struct marker_entry *entry;
- int ret = 0, need_update = 0;
+ int ret = 0;
mutex_lock(&markers_mutex);
entry = get_marker(name);
@@ -486,11 +476,9 @@ int marker_disarm(const char *name)
ret = -EPERM;
goto end;
}
- need_update = 1;
end:
+ __marker_update_probes(NULL);
mutex_unlock(&markers_mutex);
- if (need_update)
- marker_update_probes(NULL);
return ret;
}
EXPORT_SYMBOL_GPL(marker_disarm);
_
Patches currently in -mm which might be from haveblue@xxxxxxxxxx are
markers-fix-warnings.patch
maps4-add-proportional-set-size-accounting-in-smaps.patch
maps4-rework-task_size-macros.patch
maps4-move-is_swap_pte.patch
maps4-introduce-a-generic-page-walker.patch
maps4-use-pagewalker-in-clear_refs-and-smaps.patch
maps4-simplify-interdependence-of-maps-and-smaps.patch
maps4-move-clear_refs-code-to-task_mmuc.patch
maps4-regroup-task_mmu-by-interface.patch
maps4-add-proc-pid-pagemap-interface.patch
maps4-add-proc-kpagecount-interface.patch
maps4-add-proc-kpageflags-interface.patch
maps4-make-page-monitoring-proc-file-optional.patch
hugetlb-split-alloc_huge_page-into-private-and-shared-components.patch
hugetlb-split-alloc_huge_page-into-private-and-shared-components-checkpatch-fixes.patch
hugetlb-fix-quota-management-for-private-mappings.patch
hugetlb-debit-quota-in-alloc_huge_page.patch
hugetlb-allow-bulk-updating-in-hugetlb__quota.patch
hugetlb-enforce-quotas-during-reservation-for-shared-mappings.patch
r-o-bind-mounts-stub-functions.patch
r-o-bind-mounts-elevate-write-count-opend-files.patch
r-o-bind-mounts-elevate-write-count-for-some-ioctls.patch
ext2-reservations-fix-for-r-o-bind-mounts-take-writer-count-v2.patch
r-o-bind-mounts-elevate-writer-count-for-chown-and-friends.patch
r-o-bind-mounts-make-access-use-mnt-check.patch
r-o-bind-mounts-elevate-mnt-writers-for-callers-of-vfs_mkdir.patch
r-o-bind-mounts-elevate-write-count-during-entire-ncp_ioctl.patch
r-o-bind-mounts-elevate-write-count-during-entire-ncp_ioctl-fix.patch
r-o-bind-mounts-elevate-write-count-for-link-and-symlink-calls.patch
r-o-bind-mounts-elevate-mount-count-for-extended-attributes.patch
r-o-bind-mounts-elevate-write-count-for-file_update_time.patch
r-o-bind-mounts-unix_find_other-elevate-write-count-for-touch_atime.patch
r-o-bind-mounts-unix_find_other-elevate-write-count-for-touch_atime-fix.patch
r-o-bind-mounts-elevate-write-count-over-calls-to-vfs_rename.patch
r-o-bind-mounts-nfs-check-mnt-instead-of-superblock-directly.patch
r-o-bind-mounts-elevate-writer-count-for-do_sys_truncate.patch
r-o-bind-mounts-elevate-write-count-for-do_utimes.patch
r-o-bind-mounts-elevate-write-count-for-do_utimes-touch-command-causes-oops.patch
r-o-bind-mounts-elevate-write-count-for-do_sys_utime-and-touch_atime.patch
r-o-bind-mounts-sys_mknodat-elevate-write-count-for-vfs_mknod-create.patch
r-o-bind-mounts-sys_mknodat-elevate-write-count-for-vfs_mknod-create-fix.patch
r-o-bind-mounts-elevate-mnt-writers-for-vfs_unlink-callers.patch
r-o-bind-mounts-do_rmdir-elevate-write-count.patch
r-o-bind-mounts-track-number-of-mount-writers.patch
r-o-bind-mounts-track-number-of-mount-writers-make-lockdep-happy-with-r-o-bind-mounts.patch
r-o-bind-mounts-track-number-of-mount-writers-fix.patch
r-o-bind-mounts-honor-r-w-changes-at-do_remount-time.patch
reiser4.patch
page-owner-tracking-leak-detector.patch
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