total_size is sum of record->size and record->ecc_notice_size (ECC: No errors detected). When ECC is not used, then there is no problem. When ECC is enabled, then ftrace dump is decoded incorrectly after restart.
First this affects starting offset calculation, that breaks reading of all ftrace records. CPU:66 ts:51646260179894273 3818ffff80008002 fe00ffff800080f0 0x3818ffff80008002 <- 0xfe00ffff800080f0 CPU:66 ts:56589664458375169 3818ffff80008002 ff02ffff800080f0 0x3818ffff80008002 <- 0xff02ffff800080f0 CPU:67 ts:13194139533313 afe4ffff80008002 1ffff800080f0 0xafe4ffff80008002 <- 0x1ffff800080f0 CPU:67 ts:13194139533313 b7d0ffff80008001 100ffff80008002 0xb7d0ffff80008001 <- 0x100ffff80008002 CPU:67 ts:51646260179894273 8de0ffff80008001 202ffff80008002 0x8de0ffff80008001 <- 0x202ffff80008002 Second ECC notice message is printed like ftrace record and as a result couple of last records are completely wrong. For example, when the starting offset is fixed: CPU:0 ts:113 ffffffc00879bd04 ffffffc0080dc08c cpuidle_enter <- do_idle+0x20c/0x290 CPU:0 ts:114 ffffffc00879bd04 ffffffc0080dc08c cpuidle_enter <- do_idle+0x20c/0x290 CPU:100 ts:28259048229270629 6f4e203a4343450a 2073726f72726520 0x6f4e203a4343450a <- 0x2073726f72726520 Signed-off-by: Andrey Skvortsov <[email protected]> --- fs/pstore/inode.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c index b4e55c90f8dc2..9c2d5e5f31d65 100644 --- a/fs/pstore/inode.c +++ b/fs/pstore/inode.c @@ -74,9 +74,9 @@ static void *pstore_ftrace_seq_start(struct seq_file *s, loff_t *pos) if (!data) return NULL; - data->off = ps->total_size % REC_SIZE; + data->off = ps->record->size % REC_SIZE; data->off += *pos * REC_SIZE; - if (data->off + REC_SIZE > ps->total_size) + if (data->off + REC_SIZE > ps->record->size) return NULL; return_ptr(data); @@ -94,7 +94,7 @@ static void *pstore_ftrace_seq_next(struct seq_file *s, void *v, loff_t *pos) (*pos)++; data->off += REC_SIZE; - if (data->off + REC_SIZE > ps->total_size) + if (data->off + REC_SIZE > ps->record->size) return NULL; return data; -- 2.51.0
