path: root/ipc
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authorKees Cook <keescook@chromium.org>2019-09-25 16:48:11 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-09-25 17:51:41 -0700
commita44f71a9ab99b509fec9d5a9f5c222debd89934f (patch)
treee39e98ccf0774c0ef7c6f8fe30ac865fe70c3cda /ipc
parentbug: consolidate __WARN_FLAGS usage (diff)
bug: move WARN_ON() "cut here" into exception handler
The original clean up of "cut here" missed the WARN_ON() case (that does not have a printk message), which was fixed recently by adding an explicit printk of "cut here". This had the downside of adding a printk() to every WARN_ON() caller, which reduces the utility of using an instruction exception to streamline the resulting code. By making this a new BUGFLAG, all of these can be removed and "cut here" can be handled by the exception handler. This was very pronounced on PowerPC, but the effect can be seen on x86 as well. The resulting text size of a defconfig build shows some small savings from this patch: text data bss dec hex filename 19691167 5134320 1646664 26472151 193eed7 vmlinux.before 19676362 5134260 1663048 26473670 193f4c6 vmlinux.after This change also opens the door for creating something like BUG_MSG(), where a custom printk() before issuing BUG(), without confusing the "cut here" line. Link: http://lkml.kernel.org/r/201908200943.601DD59DCE@keescook Fixes: 6b15f678fb7d ("include/asm-generic/bug.h: fix "cut here" for WARN_ON for __WARN_TAINT architectures") Signed-off-by: Kees Cook <keescook@chromium.org> Reported-by: Christophe Leroy <christophe.leroy@c-s.fr> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Christophe Leroy <christophe.leroy@c-s.fr> Cc: Drew Davenport <ddavenport@chromium.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: "Steven Rostedt (VMware)" <rostedt@goodmis.org> Cc: Feng Tang <feng.tang@intel.com> Cc: Petr Mladek <pmladek@suse.com> Cc: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Cc: Borislav Petkov <bp@suse.de> Cc: YueHaibing <yuehaibing@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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