| Message ID | 4-v3-960f17f90f17+516-fwctl_jgg@nvidia.com |
|---|---|
| State | New |
| Headers | show |
| Series | Introduce fwctl subystem | expand |
On Wed, Aug 21, 2024 at 03:10:56PM -0300, Jason Gunthorpe wrote: > Requesting a fwctl scope of access that includes mutating device debug > data will cause the kernel to be tainted. Changing the device operation > through things in the debug scope may cause the device to malfunction in > undefined ways. This should be reflected in the TAINT flags to help any > debuggers understand that something has been done. I know naming is hard, but the word "fwctl" is rough, don't you think? It's become much more than just a random driver in the kernel tree, it's now a taint flag and is exposed to userspace. So I think you need to rename it to something that is at least pronouncable when talking about it (i.e. something with vowels...) There's no need to keep it in 8 or less characters, this isn't the 1970's anymore, we have enough room for everyone to spell things out now. :) thanks, greg k-h
On Thu, Aug 22, 2024 at 07:35:20AM +0800, Greg Kroah-Hartman wrote: > On Wed, Aug 21, 2024 at 03:10:56PM -0300, Jason Gunthorpe wrote: > > Requesting a fwctl scope of access that includes mutating device debug > > data will cause the kernel to be tainted. Changing the device operation > > through things in the debug scope may cause the device to malfunction in > > undefined ways. This should be reflected in the TAINT flags to help any > > debuggers understand that something has been done. > > I know naming is hard, but the word "fwctl" is rough, don't you think? > It's become much more than just a random driver in the kernel tree, it's > now a taint flag and is exposed to userspace. So I think you need to > rename it to something that is at least pronouncable when talking about > it (i.e. something with vowels...) Okay, that makes sense to me. We could also choose a different name for the taint flag. Let's see if some people have some ideas, I don't have a ready alternative.. We've just been calling it "firwmare control" in conversation Thanks, Jason
diff --git a/Documentation/admin-guide/tainted-kernels.rst b/Documentation/admin-guide/tainted-kernels.rst index f92551539e8a66..f91a54966a9719 100644 --- a/Documentation/admin-guide/tainted-kernels.rst +++ b/Documentation/admin-guide/tainted-kernels.rst @@ -101,6 +101,7 @@ Bit Log Number Reason that got the kernel tainted 16 _/X 65536 auxiliary taint, defined for and used by distros 17 _/T 131072 kernel was built with the struct randomization plugin 18 _/N 262144 an in-kernel test has been run + 19 _/J 524288 userspace used a mutating debug operation in fwctl === === ====== ======================================================== Note: The character ``_`` is representing a blank in this table to make reading @@ -182,3 +183,7 @@ More detailed explanation for tainting produce extremely unusual kernel structure layouts (even performance pathological ones), which is important to know when debugging. Set at build time. + + 18) ``J`` if userpace opened /dev/fwctl/* and performed a FWTCL_RPC_DEBUG_WRITE + to use the devices debugging features. Device debugging features could + cause the device to malfunction in undefined ways. diff --git a/include/linux/panic.h b/include/linux/panic.h index 3130e0b5116b03..bf4f276be661b7 100644 --- a/include/linux/panic.h +++ b/include/linux/panic.h @@ -73,7 +73,8 @@ static inline void set_arch_panic_timeout(int timeout, int arch_default_timeout) #define TAINT_AUX 16 #define TAINT_RANDSTRUCT 17 #define TAINT_TEST 18 -#define TAINT_FLAGS_COUNT 19 +#define TAINT_FWCTL 19 +#define TAINT_FLAGS_COUNT 20 #define TAINT_FLAGS_MAX ((1UL << TAINT_FLAGS_COUNT) - 1) struct taint_flag { diff --git a/kernel/panic.c b/kernel/panic.c index f861bedc1925e7..997b18c7455cd4 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -502,6 +502,7 @@ const struct taint_flag taint_flags[TAINT_FLAGS_COUNT] = { TAINT_FLAG(AUX, 'X', ' ', true), TAINT_FLAG(RANDSTRUCT, 'T', ' ', true), TAINT_FLAG(TEST, 'N', ' ', true), + TAINT_FLAG(FWCTL, 'J', ' ', true), }; #undef TAINT_FLAG diff --git a/tools/debugging/kernel-chktaint b/tools/debugging/kernel-chktaint index 279be06332be99..e7da0909d09707 100755 --- a/tools/debugging/kernel-chktaint +++ b/tools/debugging/kernel-chktaint @@ -204,6 +204,14 @@ else echo " * an in-kernel test (such as a KUnit test) has been run (#18)" fi +T=`expr $T / 2` +if [ `expr $T % 2` -eq 0 ]; then + addout " " +else + addout "J" + echo " * fwctl's mutating debug interface was used (#19)" +fi + echo "For a more detailed explanation of the various taint flags see" echo " Documentation/admin-guide/tainted-kernels.rst in the Linux kernel sources" echo " or https://kernel.org/doc/html/latest/admin-guide/tainted-kernels.html"
Requesting a fwctl scope of access that includes mutating device debug data will cause the kernel to be tainted. Changing the device operation through things in the debug scope may cause the device to malfunction in undefined ways. This should be reflected in the TAINT flags to help any debuggers understand that something has been done. Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> --- Documentation/admin-guide/tainted-kernels.rst | 5 +++++ include/linux/panic.h | 3 ++- kernel/panic.c | 1 + tools/debugging/kernel-chktaint | 8 ++++++++ 4 files changed, 16 insertions(+), 1 deletion(-)