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| author | Arnaldo Carvalho de Melo <acme@redhat.com> | 2020-08-06 14:15:47 +0300 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2020-08-06 14:15:47 +0300 |
| commit | 94fb1afb14c4f0ceb8c5508ddddac6819f662e95 (patch) | |
| tree | 4988e5769dc7482caa7f441475ae31f50bbd37ef /Documentation/ABI/testing/dev-kmsg | |
| parent | c4735d990268399da9133b0ad445e488ece009ad (diff) | |
| parent | 47ec5303d73ea344e84f46660fff693c57641386 (diff) | |
| download | linux-94fb1afb14c4f0ceb8c5508ddddac6819f662e95.tar.xz | |
Mgerge remote-tracking branch 'torvalds/master' into perf/core
To sync headers, for instance, in this case tools/perf was ahead of
upstream till Linus merged tip/perf/core to get the
PERF_RECORD_TEXT_POKE changes:
Warning: Kernel ABI header at 'tools/include/uapi/linux/perf_event.h' differs from latest version at 'include/uapi/linux/perf_event.h'
diff -u tools/include/uapi/linux/perf_event.h include/uapi/linux/perf_event.h
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'Documentation/ABI/testing/dev-kmsg')
| -rw-r--r-- | Documentation/ABI/testing/dev-kmsg | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/dev-kmsg b/Documentation/ABI/testing/dev-kmsg index f307506eb54c..3c0bb76e3417 100644 --- a/Documentation/ABI/testing/dev-kmsg +++ b/Documentation/ABI/testing/dev-kmsg @@ -56,6 +56,17 @@ Description: The /dev/kmsg character device node provides userspace access seek after the last record available at the time the last SYSLOG_ACTION_CLEAR was issued. + Other seek operations or offsets are not supported because of + the special behavior this device has. The device allows to read + or write only whole variable length messages (records) that are + stored in a ring buffer. + + Because of the non-standard behavior also the error values are + non-standard. -ESPIPE is returned for non-zero offset. -EINVAL + is returned for other operations, e.g. SEEK_CUR. This behavior + and values are historical and could not be modified without the + risk of breaking userspace. + The output format consists of a prefix carrying the syslog prefix including priority and facility, the 64 bit message sequence number and the monotonic timestamp in microseconds, |