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* [PATCH v1 1/1] pstore/ram: Fix crash when setting number of cpus to an odd number
@ 2023-02-24  2:36 Weichen Chen
  2023-02-24  4:00 ` Guilherme G. Piccoli
                   ` (2 more replies)
  0 siblings, 3 replies; 5+ messages in thread
From: Weichen Chen @ 2023-02-24  2:36 UTC (permalink / raw)
  To: weichen.chen, yt.shen, darren.chen, keescook, tony.luck,
	angelogioacchino.delregno, matthias.bgg, gpiccoli,
	linux-hardening, linux-kernel

When the number of cpu cores is adjusted to 7 or other odd numbers,
the zone size will become an odd number.
The address of the zone will become:
    addr of zone0 = BASE
    addr of zone1 = BASE + zone_size
    addr of zone2 = BASE + zone_size*2
    ...
The address of zone1/3/5/7 will be mapped to non-alignment va.
Eventually crashes will occur when accessing these va.

So, use ALIGN_DOWN() to make sure the zone size is even
to avoid this bug.

Signed-off-by: Weichen Chen <weichen.chen@mediatek.com>
---
 fs/pstore/ram.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
index ade66dbe5f39..fc57ac97e506 100644
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -528,6 +528,7 @@ static int ramoops_init_przs(const char *name,
 	}
 
 	zone_sz = mem_sz / *cnt;
+	zone_sz = ALIGN_DOWN(zone_sz, 2);
 	if (!zone_sz) {
 		dev_err(dev, "%s zone size == 0\n", name);
 		goto fail;
-- 
2.18.0


^ permalink raw reply related	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2023-11-08 22:47 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2023-02-24  2:36 [PATCH v1 1/1] pstore/ram: Fix crash when setting number of cpus to an odd number Weichen Chen
2023-02-24  4:00 ` Guilherme G. Piccoli
2023-02-24 10:07   ` Matthias Brugger
2023-02-24  7:05 ` Miko Larsson
2023-11-08 22:42 ` Kees Cook

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