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| author | Peng Wang <wangpeng15@xiaomi.com> | 2018-10-30 08:52:34 +0100 |
|---|---|---|
| committer | Kees Cook <keescook@chromium.org> | 2018-12-04 01:52:35 +0100 |
| commit | 7684bd334d9d4ca4f09873e88d9c0131a2cf6c3b (patch) | |
| tree | 2ccb5d56ff8945abd6d2a85bb70e8804ba6bef9c /fs/pstore | |
| parent | pstore: Remove needless lock during console writes (diff) | |
| download | linux-7684bd334d9d4ca4f09873e88d9c0131a2cf6c3b.tar.xz linux-7684bd334d9d4ca4f09873e88d9c0131a2cf6c3b.zip | |
pstore: Avoid duplicate call of persistent_ram_zap()
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>
Diffstat (limited to 'fs/pstore')
| -rw-r--r-- | fs/pstore/ram.c | 4 | ||||
| -rw-r--r-- | fs/pstore/ram_core.c | 15 |
2 files changed, 10 insertions, 9 deletions
diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c index e02a9039b5ea..768759841491 100644 --- a/fs/pstore/ram.c +++ b/fs/pstore/ram.c @@ -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; diff --git a/fs/pstore/ram_core.c b/fs/pstore/ram_core.c index 12e21f789194..23ca6f2c98a0 100644 --- a/fs/pstore/ram_core.c +++ b/fs/pstore/ram_core.c @@ -489,6 +489,7 @@ static int persistent_ram_post_init(struct persistent_ram_zone *prz, u32 sig, struct persistent_ram_ecc_info *ecc_info) { int ret; + bool zap = !!(prz->flags & PRZ_FLAG_ZAP_OLD); ret = persistent_ram_init_ecc(prz, ecc_info); if (ret) @@ -498,23 +499,25 @@ static int persistent_ram_post_init(struct persistent_ram_zone *prz, u32 sig, if (prz->buffer->sig == sig) { if (buffer_size(prz) > prz->buffer_size || - buffer_start(prz) > buffer_size(prz)) + buffer_start(prz) > buffer_size(prz)) { pr_info("found existing invalid buffer, size %zu, start %zu\n", buffer_size(prz), buffer_start(prz)); - else { + zap = true; + } else { pr_debug("found existing buffer, size %zu, start %zu\n", buffer_size(prz), buffer_start(prz)); persistent_ram_save_old(prz); - return 0; } } else { pr_debug("no valid data in buffer (sig = 0x%08x)\n", prz->buffer->sig); + prz->buffer->sig = sig; + zap = true; } - /* Rewind missing or invalid memory area. */ - prz->buffer->sig = sig; - persistent_ram_zap(prz); + /* Reset missing, invalid, or single-use memory area. */ + if (zap) + persistent_ram_zap(prz); return 0; } |