diff options
author | 2020-08-14 23:31:25 +0206 | |
---|---|---|
committer | 2020-09-08 09:33:15 +0200 | |
commit | e60768311af854734ce2bbfc50f24cff67b54a91 (patch) | |
tree | ff1470642d64b9b5639749e7fbd8eeac4fecf1a8 /Documentation/admin-guide/kdump | |
parent | scripts/gdb: add utils.read_ulong() (diff) | |
download | linux-e60768311af854734ce2bbfc50f24cff67b54a91.tar.gz linux-e60768311af854734ce2bbfc50f24cff67b54a91.tar.bz2 linux-e60768311af854734ce2bbfc50f24cff67b54a91.zip |
scripts/gdb: update for lockless printk ringbuffer
With the introduction of the lockless printk ringbuffer, the data
structure for the kernel log buffer was changed. Update the gdb
scripts to be able to parse/print the new log buffer structure.
Fixes: 896fbe20b4e2333fb55 ("printk: use the lockless ringbuffer")
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reported-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Petr Mladek <pmladek@suse.com>
[akpm@linux-foundation.org: A typo fix.]
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20200814212525.6118-3-john.ogness@linutronix.de
Diffstat (limited to 'Documentation/admin-guide/kdump')
-rw-r--r-- | Documentation/admin-guide/kdump/gdbmacros.txt | 153 |
1 files changed, 107 insertions, 46 deletions
diff --git a/Documentation/admin-guide/kdump/gdbmacros.txt b/Documentation/admin-guide/kdump/gdbmacros.txt index 220d0a80ca2c..7adece30237e 100644 --- a/Documentation/admin-guide/kdump/gdbmacros.txt +++ b/Documentation/admin-guide/kdump/gdbmacros.txt @@ -170,57 +170,111 @@ document trapinfo address the kernel panicked. end -define dump_log_idx - set $idx = $arg0 +define dump_record + set var $desc = $arg0 if ($argc > 1) - set $prev_flags = $arg1 + set var $prev_flags = $arg1 else - set $prev_flags = 0 + set var $prev_flags = 0 end - set $msg = ((struct printk_log *) (log_buf + $idx)) - set $prefix = 1 - set $newline = 1 - set $log = log_buf + $idx + sizeof(*$msg) - - # prev & LOG_CONT && !(msg->flags & LOG_PREIX) - if (($prev_flags & 8) && !($msg->flags & 4)) - set $prefix = 0 + + set var $info = &$desc->info + set var $prefix = 1 + set var $newline = 1 + + set var $begin = $desc->text_blk_lpos.begin % (1U << prb->text_data_ring.size_bits) + set var $next = $desc->text_blk_lpos.next % (1U << prb->text_data_ring.size_bits) + + # handle data-less record + if ($begin & 1) + set var $text_len = 0 + set var $log = "" + else + # handle wrapping data block + if ($begin > $next) + set var $begin = 0 + end + + # skip over descriptor id + set var $begin = $begin + sizeof(long) + + # handle truncated message + if ($next - $begin < $info->text_len) + set var $text_len = $next - $begin + else + set var $text_len = $info->text_len + end + + set var $log = &prb->text_data_ring.data[$begin] + end + + # prev & LOG_CONT && !(info->flags & LOG_PREIX) + if (($prev_flags & 8) && !($info->flags & 4)) + set var $prefix = 0 end - # msg->flags & LOG_CONT - if ($msg->flags & 8) + # info->flags & LOG_CONT + if ($info->flags & 8) # (prev & LOG_CONT && !(prev & LOG_NEWLINE)) if (($prev_flags & 8) && !($prev_flags & 2)) - set $prefix = 0 + set var $prefix = 0 end - # (!(msg->flags & LOG_NEWLINE)) - if (!($msg->flags & 2)) - set $newline = 0 + # (!(info->flags & LOG_NEWLINE)) + if (!($info->flags & 2)) + set var $newline = 0 end end if ($prefix) - printf "[%5lu.%06lu] ", $msg->ts_nsec / 1000000000, $msg->ts_nsec % 1000000000 + printf "[%5lu.%06lu] ", $info->ts_nsec / 1000000000, $info->ts_nsec % 1000000000 end - if ($msg->text_len != 0) - eval "printf \"%%%d.%ds\", $log", $msg->text_len, $msg->text_len + if ($text_len) + eval "printf \"%%%d.%ds\", $log", $text_len, $text_len end if ($newline) printf "\n" end - if ($msg->dict_len > 0) - set $dict = $log + $msg->text_len - set $idx = 0 - set $line = 1 - while ($idx < $msg->dict_len) + + # handle dictionary data + + set var $begin = $desc->dict_blk_lpos.begin % (1U << prb->dict_data_ring.size_bits) + set var $next = $desc->dict_blk_lpos.next % (1U << prb->dict_data_ring.size_bits) + + # handle data-less record + if ($begin & 1) + set var $dict_len = 0 + set var $dict = "" + else + # handle wrapping data block + if ($begin > $next) + set var $begin = 0 + end + + # skip over descriptor id + set var $begin = $begin + sizeof(long) + + # handle truncated message + if ($next - $begin < $info->dict_len) + set var $dict_len = $next - $begin + else + set var $dict_len = $info->dict_len + end + + set var $dict = &prb->dict_data_ring.data[$begin] + end + + if ($dict_len > 0) + set var $idx = 0 + set var $line = 1 + while ($idx < $dict_len) if ($line) printf " " - set $line = 0 + set var $line = 0 end - set $c = $dict[$idx] + set var $c = $dict[$idx] if ($c == '\0') printf "\n" - set $line = 1 + set var $line = 1 else if ($c < ' ' || $c >= 127 || $c == '\\') printf "\\x%02x", $c @@ -228,33 +282,40 @@ define dump_log_idx printf "%c", $c end end - set $idx = $idx + 1 + set var $idx = $idx + 1 end printf "\n" end end -document dump_log_idx - Dump a single log given its index in the log buffer. The first - parameter is the index into log_buf, the second is optional and - specified the previous log buffer's flags, used for properly - formatting continued lines. +document dump_record + Dump a single record. The first parameter is the descriptor + sequence number, the second is optional and specifies the + previous record's flags, used for properly formatting + continued lines. end define dmesg - set $i = log_first_idx - set $end_idx = log_first_idx - set $prev_flags = 0 + set var $desc_committed = 1UL << ((sizeof(long) * 8) - 1) + set var $flags_mask = 3UL << ((sizeof(long) * 8) - 2) + set var $id_mask = ~$flags_mask + + set var $desc_count = 1U << prb->desc_ring.count_bits + set var $prev_flags = 0 + + set var $id = prb->desc_ring.tail_id.counter + set var $end_id = prb->desc_ring.head_id.counter while (1) - set $msg = ((struct printk_log *) (log_buf + $i)) - if ($msg->len == 0) - set $i = 0 - else - dump_log_idx $i $prev_flags - set $i = $i + $msg->len - set $prev_flags = $msg->flags + set var $desc = &prb->desc_ring.descs[$id % $desc_count] + + # skip non-committed record + if (($desc->state_var.counter & $flags_mask) == $desc_committed) + dump_record $desc $prev_flags + set var $prev_flags = $desc->info.flags end - if ($i == $end_idx) + + set var $id = ($id + 1) & $id_mask + if ($id == $end_id) loop_break end end |