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SubjectRe: [PATCH v2] proc/vmcore: fix potential memory leak in vmcore_init()
On 07/08/22 at 04:34pm, Baoquan He wrote:
> On 07/04/22 at 04:18pm, Jianglei Nie wrote:
> > elfcorehdr_alloc() allocates a memory chunk for elfcorehdr_addr with
> > kzalloc(). If is_vmcore_usable() returns false, elfcorehdr_addr is a
> > predefined value. If parse_crash_elf_headers() occurs some error and
> > returns a negetive value, the elfcorehdr_addr should be released with
> > elfcorehdr_free().
> >
> > We can fix by calling elfcorehdr_free() when parse_crash_elf_headers()
> > fails.
>
> LGTM,
>
> Acked-by: Baoquan He <bhe@redhat.com>

Sorry, I didn't check the code change carefully. This v2 is not right. I
thought Jianglei took my suggested code change directly. Seems he
mistakenly took part of them and caused error.

>
> >
> > Signed-off-by: Jianglei Nie <niejianglei2021@163.com>
> > ---
> > fs/proc/vmcore.c | 5 ++++-
> > 1 file changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
> > index 4eaeb645e759..86887bd90263 100644
> > --- a/fs/proc/vmcore.c
> > +++ b/fs/proc/vmcore.c
> > @@ -1569,7 +1569,7 @@ static int __init vmcore_init(void)
> > rc = parse_crash_elf_headers();
> > if (rc) {
> > pr_warn("Kdump: vmcore not initialized\n");
> > - return rc;
> > + goto fail;
> > }
> > elfcorehdr_free(elfcorehdr_addr);
~~
this line should be removed.
> > elfcorehdr_addr = ELFCORE_ADDR_ERR;
> > @@ -1577,6 +1577,9 @@ static int __init vmcore_init(void)
> > proc_vmcore = proc_create("vmcore", S_IRUSR, NULL, &vmcore_proc_ops);
> > if (proc_vmcore)
> > proc_vmcore->size = vmcore_size;
> > +
> > +fail:
> > + elfcorehdr_free(elfcorehdr_addr);
> > return 0;
^
return rc; the returned value is wrong with v2.

What I suggested is as below.

Andrew, please drop the one merged into mm-unstable branch.

Hi Jianglei,

Can you post v3 with below correct change and add Andrew to CC?

diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
index 4eaeb645e759..390515c249dd 100644
--- a/fs/proc/vmcore.c
+++ b/fs/proc/vmcore.c
@@ -1569,15 +1569,16 @@ static int __init vmcore_init(void)
rc = parse_crash_elf_headers();
if (rc) {
pr_warn("Kdump: vmcore not initialized\n");
- return rc;
+ goto fail;
}
- elfcorehdr_free(elfcorehdr_addr);
elfcorehdr_addr = ELFCORE_ADDR_ERR;

proc_vmcore = proc_create("vmcore", S_IRUSR, NULL, &vmcore_proc_ops);
if (proc_vmcore)
proc_vmcore->size = vmcore_size;
- return 0;
+fail:
+ elfcorehdr_free(elfcorehdr_addr);
+ return rc;
}
fs_initcall(vmcore_init);

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