mpol_to_str() may fail, and not fill the buffer (e.g. -EINVAL), so need
check about it, or buffer may not be zero based, and next seq_printf()
will cause issue.
Also print related warning when the buffer space is not enough.
Signed-off-by: Chen Gang <gang.chen@xxxxxxxxxxx>
---
fs/proc/task_mmu.c | 16 ++++++++++++++--
1 files changed, 14 insertions(+), 2 deletions(-)
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index a117207..1cb7445 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -1359,7 +1359,7 @@ static int show_numa_map(struct seq_file *m, void *v, int is_pid)
struct mm_struct *mm = vma->vm_mm;
struct mm_walk walk = {};
struct mempolicy *pol;
- int n;
+ int n, ret;
char buffer[50];
if (!mm)
@@ -1376,7 +1376,19 @@ static int show_numa_map(struct seq_file *m, void *v, int is_pid)
walk.mm = mm;
pol = get_vma_policy(task, vma, vma->vm_start);
- mpol_to_str(buffer, sizeof(buffer), pol);
+ ret = mpol_to_str(buffer, sizeof(buffer), pol);
+ if (ret < 0)
+ switch (ret) {
+ case -ENOSPC:
+ pr_warn("in %s: string is truncated in mpol_to_str().\n",
+ __func__);
+ break;
+ default:
+ pr_err("in %s: call mpol_to_str() fail, errcode: %d. buffer: %p, size: %zu, pol: %p\n",
+ __func__, ret, buffer, sizeof(buffer), pol);
+ return ret;
+ }
+
mpol_cond_put(pol);
seq_printf(m, "%08lx %s", vma->vm_start, buffer);
--
1.7.7.6
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