lkml.org 
[lkml]   [2022]   [Oct]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: [PATCH 1/1] pstore/ram: Ensure stable pmsg address with per-CPU ftrace buffers
On Tue, Oct 11, 2022 at 11:36:31AM -0700, pso@chromium.org wrote:
> From: Paramjit Oberoi <psoberoi@google.com>
>
> When allocating ftrace pstore zones, there may be space left over at the
> end of the region. The paddr pointer needs to be advanced to account for
> this so that the next region (pmsg) ends up at the correct location.
>
> Signed-off-by: Paramjit Oberoi <pso@chromium.org>
> Reviewed-by: Dmitry Torokhov <dtor@chromium.org>
> Signed-off-by: Paramjit Oberoi <psoberoi@google.com>

Hm, interesting point. Since only ftrace is dynamically sized in this
fashion, how about just moving the pmsg allocation before ftrace, and
adding a comment that for now ftrace should be allocated last?

i.e. something like:

diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
index 650f89c8ae36..9e11d3e7dffe 100644
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -788,6 +788,11 @@ static int ramoops_probe(struct platform_device *pdev)
if (err)
goto fail_init;

+ err = ramoops_init_prz("pmsg", dev, cxt, &cxt->mprz, &paddr,
+ cxt->pmsg_size, 0);
+ if (err)
+ goto fail_init;
+
cxt->max_ftrace_cnt = (cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU)
? nr_cpu_ids
: 1;
@@ -799,11 +804,6 @@ static int ramoops_probe(struct platform_device *pdev)
if (err)
goto fail_init;

- err = ramoops_init_prz("pmsg", dev, cxt, &cxt->mprz, &paddr,
- cxt->pmsg_size, 0);
- if (err)
- goto fail_init;
-
cxt->pstore.data = cxt;
/*
* Prepare frontend flags based on which areas are initialized.
(Note that this won't apply to the current tree, where I've started some
other refactoring.)

--
Kees Cook

\
 
 \ /
  Last update: 2022-10-11 21:39    [W:0.062 / U:0.920 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site