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pstore: Avoid duplicate call of persistent_ram_zap()

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When initialing a prz, if invalid data is found (no PERSISTENT_RAM_SIG),
the function call path looks like this:

ramoops_init_prz ->
    persistent_ram_new -> persistent_ram_post_init -> persistent_ram_zap
    persistent_ram_zap

As we can see, persistent_ram_zap() is called twice.
We can avoid this by adding an option to persistent_ram_new(), and
only call persistent_ram_zap() when it is needed.

Signed-off-by: Peng Wang <wangpeng15@xiaomi.com>
[kees: minor tweak to exit path and commit log]
Signed-off-by: Kees Cook <keescook@chromium.org>
This commit is contained in:
Peng Wang
2018-10-30 15:52:34 +08:00
committed by Kees Cook
parent b77fa617a2
commit 7684bd334d
3 changed files with 11 additions and 9 deletions
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4
fs/pstore/ram.c
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@@ -640,7 +640,7 @@ static int ramoops_init_prz(const char *name,
label = kasprintf(GFP_KERNEL, "ramoops:%s", name);
*prz = persistent_ram_new(*paddr, sz, sig, &cxt->ecc_info,
cxt->memtype, 0, label);
cxt->memtype, PRZ_FLAG_ZAP_OLD, label);
if (IS_ERR(*prz)) {
int err = PTR_ERR(*prz);
@@ -649,8 +649,6 @@ static int ramoops_init_prz(const char *name,
return err;
}
persistent_ram_zap(*prz);
*paddr += sz;
return 0;