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Message-Id: <20190729190825.269610232@linuxfoundation.org>
Date: Mon, 29 Jul 2019 21:18:49 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Borislav Petkov <bp@...e.de>,
Tony Luck <tony.luck@...el.com>,
linux-edac <linux-edac@...r.kernel.org>,
Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.14 038/293] RAS/CEC: Fix pfn insertion
[ Upstream commit 6d8e294bf5f0e85c34e8b14b064e2965f53f38b0 ]
When inserting random PFNs for debugging the CEC through
(debugfs)/ras/cec/pfn, depending on the return value of pfn_set(),
multiple values get inserted per a single write.
That is because simple_attr_write() interprets a retval of 0 as
success and claims the whole input. However, pfn_set() returns the
cec_add_elem() value, which, if > 0 and smaller than the whole input
length, makes glibc continue issuing the write syscall until there's
input left:
pfn_set
simple_attr_write
debugfs_attr_write
full_proxy_write
vfs_write
ksys_write
do_syscall_64
entry_SYSCALL_64_after_hwframe
leading to those repeated calls.
Return 0 to fix that.
Signed-off-by: Borislav Petkov <bp@...e.de>
Cc: Tony Luck <tony.luck@...el.com>
Cc: linux-edac <linux-edac@...r.kernel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
drivers/ras/cec.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/ras/cec.c b/drivers/ras/cec.c
index c7205cdcc11a..97cf40a522be 100644
--- a/drivers/ras/cec.c
+++ b/drivers/ras/cec.c
@@ -373,7 +373,9 @@ static int pfn_set(void *data, u64 val)
{
*(u64 *)data = val;
- return cec_add_elem(val);
+ cec_add_elem(val);
+
+ return 0;
}
DEFINE_DEBUGFS_ATTRIBUTE(pfn_ops, u64_get, pfn_set, "0x%llx\n");
--
2.20.1
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