From 8eea4e74475804285507c077bec87d40be87ff06 Mon Sep 17 00:00:00 2001 From: Jason Gunthorpe Date: Thu, 27 Feb 2025 20:26:32 -0400 Subject: [PATCH] taint: Add TAINT_FWCTL 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. Link: https://patch.msgid.link/r/4-v5-642aa0c94070+4447f-fwctl_jgg@nvidia.com Reviewed-by: Jonathan Cameron Reviewed-by: Dave Jiang Reviewed-by: Shannon Nelson Tested-by: Dave Jiang Tested-by: Shannon Nelson Signed-off-by: Jason Gunthorpe --- 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(-) diff --git a/Documentation/admin-guide/tainted-kernels.rst b/Documentation/admin-guide/tainted-kernels.rst index 700aa72eecb16..a0cc017e44246 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 @@ -184,3 +185,7 @@ More detailed explanation for tainting build time. 18) ``N`` if an in-kernel test, such as a KUnit test, has been run. + + 19) ``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 54d90b6c5f47b..2494d51707ef4 100644 --- a/include/linux/panic.h +++ b/include/linux/panic.h @@ -74,7 +74,8 @@ 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 d8635d5cecb25..0c55eec9e8744 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -511,6 +511,7 @@ 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 279be06332be9..e7da0909d0970 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"