| Message ID | 1491343938-75336-2-git-send-email-keescook@chromium.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > index 77fadface4f9..5ac4d1148385 100644 > --- a/lib/Kconfig.debug > +++ b/lib/Kconfig.debug > @@ -1998,9 +1998,12 @@ config BUG_ON_DATA_CORRUPTION > > bool "Trigger a BUG when data corruption is detected" > > select DEBUG_LIST > > help > > - Select this option if the kernel should BUG when it encounters > > - data corruption in kernel memory structures when they get checked > > - for validity. > > + This option enables several inexpensive data corruption checks. > > + Most of these checks normally just WARN and try to further avoid > + the corruption. Selecting this option upgrades these to BUGs so First it says it enables some checks, but here it says it upgrades them to BUGs which seems inconsistent. > + that the offending process is killed. Additionally, the system > + owner can furhter configure the system for immediate reboots "further" > + (via panic_on_oops sysctl) or crash dumps. > > > If unsure, say N. >
On Tue, Apr 4, 2017 at 10:47 PM, Ian Campbell <ijc@hellion.org.uk> wrote: >> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug >> index 77fadface4f9..5ac4d1148385 100644 >> --- a/lib/Kconfig.debug >> +++ b/lib/Kconfig.debug >> @@ -1998,9 +1998,12 @@ config BUG_ON_DATA_CORRUPTION >> > bool "Trigger a BUG when data corruption is detected" >> > select DEBUG_LIST >> > help >> > - Select this option if the kernel should BUG when it encounters >> > - data corruption in kernel memory structures when they get checked >> > - for validity. >> > + This option enables several inexpensive data corruption checks. >> > + Most of these checks normally just WARN and try to further avoid >> + the corruption. Selecting this option upgrades these to BUGs so > > First it says it enables some checks, but here it says it upgrades them > to BUGs which seems inconsistent. Right, it does both. It uses Kconfig "select" to enable checks, and raises checks from WARN to BUG. > >> + that the offending process is killed. Additionally, the system >> + owner can furhter configure the system for immediate reboots > > "further" Ah, thanks! > >> + (via panic_on_oops sysctl) or crash dumps. >> >> > If unsure, say N. >> -Kees
diff --git a/include/linux/bug.h b/include/linux/bug.h index 687b557fc5eb..db1e41c69bac 100644 --- a/include/linux/bug.h +++ b/include/linux/bug.h @@ -124,7 +124,8 @@ static inline enum bug_trap_type report_bug(unsigned long bug_addr, /* * Since detected data corruption should stop operation on the affected - * structures. Return value must be checked and sanely acted on by caller. + * structures, require that the condition is checked and sanely acted on + * by the caller. */ static inline __must_check bool check_data_corruption(bool v) { return v; } #define CHECK_DATA_CORRUPTION(condition, fmt, ...) \ diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 77fadface4f9..5ac4d1148385 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1998,9 +1998,12 @@ config BUG_ON_DATA_CORRUPTION bool "Trigger a BUG when data corruption is detected" select DEBUG_LIST help - Select this option if the kernel should BUG when it encounters - data corruption in kernel memory structures when they get checked - for validity. + This option enables several inexpensive data corruption checks. + Most of these checks normally just WARN and try to further avoid + the corruption. Selecting this option upgrades these to BUGs so + that the offending process is killed. Additionally, the system + owner can furhter configure the system for immediate reboots + (via panic_on_oops sysctl) or crash dumps. If unsure, say N.
This expands on the Kconfig help text for CONFIG_BUG_ON_DATA_CORRUPTION to more clearly explain the rationale of BUG vs WARN. Additionally fixes a grammar glitch in the macro comment. Signed-off-by: Kees Cook <keescook@chromium.org> --- include/linux/bug.h | 3 ++- lib/Kconfig.debug | 9 ++++++--- 2 files changed, 8 insertions(+), 4 deletions(-)