linux-stable/drivers/ras
Borislav Petkov 0dd8efba83 RAS/CEC: Fix pfn insertion
[ Upstream commit 6d8e294bf5 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-07-31 07:28:24 +02:00
..
cec.c RAS/CEC: Fix pfn insertion 2019-07-31 07:28:24 +02:00
debugfs.c
debugfs.h
Kconfig
Makefile
ras.c