summaryrefslogtreecommitdiffstats
path: root/include/linux/hrtimer.h
diff options
context:
space:
mode:
authorDmitry Vyukov2018-08-22 06:55:24 +0200
committerLinus Torvalds2018-08-22 19:52:46 +0200
commit96c6a32ccb55a366054fd82cc63523bb7f7493d3 (patch)
treefb339e055035609ea3616e64a5a4262ccf20da65 /include/linux/hrtimer.h
parentproc/kcore: add vmcoreinfo note to /proc/kcore (diff)
downloadkernel-qcow2-linux-96c6a32ccb55a366054fd82cc63523bb7f7493d3.tar.gz
kernel-qcow2-linux-96c6a32ccb55a366054fd82cc63523bb7f7493d3.tar.xz
kernel-qcow2-linux-96c6a32ccb55a366054fd82cc63523bb7f7493d3.zip
include/asm-generic/bug.h: clarify valid uses of WARN()
Explicitly state that WARN*() should be used only for recoverable kernel issues/bugs and that it should not be used for any kind of invalid external inputs or transient conditions. Motivation: it's a very useful capability to be able to understand if a particular kernel splat means a kernel bug or simply an invalid user-space program. For the former one wants to notify kernel developers, while notifying kernel developers for the latter is annoying. Even a kernel developer may not know what to do with a WARNING in an unfamiliar subsystem. This is especially critical for any automated testing systems that may use panic_on_warn and mail kernel developers. The clear separation also serves as an additional documentation: is it a condition that must never occur because of additional checks/logic elsewhere? or is it simply a check for invalid inputs or unfortunate conditions? Use of pr_err() for user messages also leads to better error messages. "Something is wrong in file foo on line X" is not particularly useful message for end user. pr_err() forces developers to write more meaningful error messages for user. As of now we are almost there. We are doing systematic kernel testing with panic_on_warn and are not seeing massive amounts of false positives. But every now and then another WARN on ENOMEM or invalid inputs pops up and leads to a lengthy argument each time. The goal of this change is to officially document the rules. Link: http://lkml.kernel.org/r/20180620103716.61636-1-dvyukov@gmail.com Signed-off-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/hrtimer.h')
0 files changed, 0 insertions, 0 deletions