perf_event_mmap_event() does kzalloc(PATH_MAX + sizeof(u64)) to
ensure we can align the size later. However this means that we
actually allocate PAGE_SIZE * 2 buffer, seems too much.
Change this code to allocate PATH_MAX==PAGE_SIZE bytes, but tell
d_path() to not use the last sizeof(u64) bytes.
Note: it is not clear why do we need __GFP_ZERO, see the next patch.
Signed-off-by: Oleg Nesterov <o...@redhat.com>
---
kernel/events/core.c | 13 +++++++------
1 files changed, 7 insertions(+), 6 deletions(-)
diff --git a/kernel/events/core.c b/kernel/events/core.c
index e27d8f8..4a1e7b8 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -5107,17 +5107,18 @@ static void perf_event_mmap_event(struct
perf_mmap_event *mmap_event)
if (file) {
struct inode *inode;
dev_t dev;
+
+ buf = kzalloc(PATH_MAX, GFP_KERNEL);
+ if (!buf) {
+ name = strncpy(tmp, "//enomem", sizeof(tmp));
+ goto got_name;
+ }
/*
* d_path works from the end of the rb backwards, so we
* need to add enough zero bytes after the string to handle
* the 64bit alignment we do later.
*/
- buf = kzalloc(PATH_MAX + sizeof(u64), GFP_KERNEL);
- if (!buf) {
- name = strncpy(tmp, "//enomem", sizeof(tmp));
- goto got_name;
- }
- name = d_path(&file->f_path, buf, PATH_MAX);
+ name = d_path(&file->f_path, buf, PATH_MAX - sizeof(u64));
if (IS_ERR(name)) {
name = strncpy(tmp, "//toolong", sizeof(tmp));
goto got_name;
--
1.5.5.1
--
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