From: Borislav Petkov <[email protected]> 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. Rename u64_get() to pfn_get() while at it. Signed-off-by: Borislav Petkov <[email protected]> Cc: Tony Luck <[email protected]> Cc: linux-edac <[email protected]> --- drivers/ras/cec.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/drivers/ras/cec.c b/drivers/ras/cec.c index 673f8a128397..1275907ff21c 100644 --- a/drivers/ras/cec.c +++ b/drivers/ras/cec.c @@ -358,7 +358,7 @@ int cec_add_elem(u64 pfn) return ret; } -static int u64_get(void *data, u64 *val) +static int pfn_get(void *data, u64 *val) { *val = *(u64 *)data; @@ -369,10 +369,12 @@ 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"); +DEFINE_DEBUGFS_ATTRIBUTE(pfn_ops, pfn_get, pfn_set, "0x%llx\n"); static int decay_interval_set(void *data, u64 val) { @@ -389,7 +391,7 @@ static int decay_interval_set(void *data, u64 val) cec_mod_work(decay_interval); return 0; } -DEFINE_DEBUGFS_ATTRIBUTE(decay_interval_ops, u64_get, decay_interval_set, "%lld\n"); +DEFINE_DEBUGFS_ATTRIBUTE(decay_interval_ops, pfn_get, decay_interval_set, "%lld\n"); static int count_threshold_set(void *data, u64 val) { @@ -402,7 +404,7 @@ static int count_threshold_set(void *data, u64 val) return 0; } -DEFINE_DEBUGFS_ATTRIBUTE(count_threshold_ops, u64_get, count_threshold_set, "%lld\n"); +DEFINE_DEBUGFS_ATTRIBUTE(count_threshold_ops, pfn_get, count_threshold_set, "%lld\n"); static int array_dump(struct seq_file *m, void *v) { -- 2.21.0
