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RAS/CEC: Fix pfn insertion

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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@suse.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
This commit is contained in:
Borislav Petkov 2019-04-20 12:53:05 +02:00
parent 0ade0b6240
commit 6d8e294bf5
1 changed files with 3 additions and 1 deletions
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4
drivers/ras/cec.c
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@ -369,7 +369,9 @@ 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");