[igt-dev] [PATCH i-g-t] lib: Process kernel taints
Petri Latvala
petri.latvala at intel.com
Fri Jan 8 13:30:13 UTC 2021
On Fri, Jan 08, 2021 at 01:01:57PM +0000, Chris Wilson wrote:
> A small library routine to read '/proc/sys/kernel/taints' and check for
> a fatal condition. This is currently used by the runner, but is also
> useful for some tests.
>
> v2: function docs
>
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Petri Latvala <petri.latvala at intel.com>
> ---
> lib/Makefile.sources | 2 +
> lib/igt_taints.c | 98 ++++++++++++++++++++++++++++++++++++++++++++
> lib/igt_taints.h | 19 +++++++++
> lib/meson.build | 1 +
> runner/executor.c | 73 +++++++--------------------------
> 5 files changed, 134 insertions(+), 59 deletions(-)
> create mode 100644 lib/igt_taints.c
> create mode 100644 lib/igt_taints.h
>
> diff --git a/lib/Makefile.sources b/lib/Makefile.sources
> index 67b386457..7102f95e7 100644
> --- a/lib/Makefile.sources
> +++ b/lib/Makefile.sources
> @@ -64,6 +64,8 @@ lib_source_list = \
> igt_sysfs.h \
> igt_sysrq.c \
> igt_sysrq.h \
> + igt_taints.c \
> + igt_taints.h \
> igt_thread.c \
> igt_thread.h \
> igt_x86.h \
> diff --git a/lib/igt_taints.c b/lib/igt_taints.c
> new file mode 100644
> index 000000000..a5a7e6cae
> --- /dev/null
> +++ b/lib/igt_taints.c
> @@ -0,0 +1,98 @@
> +// SPDX-License-Identifier: MIT
> +/*
> + * Copyright © 2021 Intel Corporation
> + */
> +
> +#include <stdio.h>
> +
> +#include "igt_taints.h"
> +
> +/* see Linux's include/linux/kernel.h */
> +static const struct {
> + int bit;
> + int bad;
> + const char *explanation;
> +} abort_taints[] = {
> + { 5, 1, "TAINT_BAD_PAGE: Bad page reference or an unexpected page flags." },
> + { 7, 1, "TAINT_DIE: Kernel has died - BUG/OOPS." },
> + { 9, 1, "TAINT_WARN: WARN_ON has happened." },
> + { -1 }
> +};
> +
> +/**
> + * igt_explain_taints:
> + * @taints: mask of taints requiring an explanation [inout]
> + *
> + * Inspects the mask and looks up the first reason correspoding to a set
> + * bit in the mast. It returns the reason as a string constant, and removes
> + * the bit from the mask. If the mask is empty, or we have no known reason
> + * matching the match, NULL is returned.
> + *
> + * This may be used in a loop to extract all known reasons for why the
> + * kernel tained:
s/correspoding/corresponding/
s/mast/mask/
s/matching the match/matching the mask/
> + *
> + * while (reason = igt_explain_taints(&taints))
> + * igt_info("%s", reason);
> + *
> + * Returns the first reason corresponding to a taint bit.
> + */
> +const char *igt_explain_taints(unsigned long *taints)
> +{
> + for (typeof(*abort_taints) *taint = abort_taints;
> + taint->bit >= 0;
> + taint++) {
> + if (*taints & (1ul << taint->bit)) {
> + *taints &= ~(1ul << taint->bit);
> + return taint->explanation;
> + }
> + }
> +
> + return NULL;
> +}
> +
> +/**
> + * igt_bad_taints:
> + *
> + * Returns the mask of kernel taints that IGT considers fatal.
> + * Such as TAINT_WARN set when the kernel oopses.
> + */
> +unsigned long igt_bad_taints(void)
> +{
> + static unsigned long bad_taints;
> +
> + if (!bad_taints) {
> + for (typeof(*abort_taints) *taint = abort_taints;
> + taint->bit >= 0;
> + taint++) {
> + if (taint->bad)
> + bad_taints |= 1ul << taint->bit;
> + }
> + }
> +
> + return bad_taints;
> +}
> +
> +/**
> + * igt_kernel_tainted:
> + * @taints: bitmask of kernel taints [out]
> + *
> + * Reads "/prco/sys/kernel/tainted" and returns both the set of all
> + * taints reported via @taints, and the set of fatal taints as the
> + * return parameters.
> + *
> + * Returns a mask of fatal taints; 0 if untainted.
> + */
s/prco/proc/
Move the "both" word later so it's clear it's returning the same thing
with two means, instead of returning two things.
With those
Reviewed-by: Petri Latvala <petri.latvala at intel.com>
> +unsigned long igt_kernel_tainted(unsigned long *taints)
> +{
> + FILE *f;
> +
> + *taints = 0;
> +
> + f = fopen("/proc/sys/kernel/tainted", "r");
> + if (f) {
> + fscanf(f, "%lu", taints);
> + fclose(f);
> + }
> +
> + return is_tainted(*taints);
> +}
> diff --git a/lib/igt_taints.h b/lib/igt_taints.h
> new file mode 100644
> index 000000000..be4195c5a
> --- /dev/null
> +++ b/lib/igt_taints.h
> @@ -0,0 +1,19 @@
> +/* SPDX-License-Identifier: MIT */
> +/*
> + * Copyright © 2021 Intel Corporation
> + */
> +
> +#ifndef __IGT_TAINTS_H__
> +#define __IGT_TAINTS_H__
> +
> +unsigned long igt_kernel_tainted(unsigned long *taints);
> +const char *igt_explain_taints(unsigned long *taints);
> +
> +unsigned long igt_bad_taints(void);
> +
> +static inline unsigned long is_tainted(unsigned long taints)
> +{
> + return taints & igt_bad_taints();
> +}
> +
> +#endif /* __IGT_TAINTS_H__ */
> diff --git a/lib/meson.build b/lib/meson.build
> index 540facb24..3abc42cb3 100644
> --- a/lib/meson.build
> +++ b/lib/meson.build
> @@ -27,6 +27,7 @@ lib_sources = [
> 'igt_syncobj.c',
> 'igt_sysfs.c',
> 'igt_sysrq.c',
> + 'igt_taints.c',
> 'igt_thread.c',
> 'igt_vec.c',
> 'igt_vgem.c',
> diff --git a/runner/executor.c b/runner/executor.c
> index faf272d85..93db8bb36 100644
> --- a/runner/executor.c
> +++ b/runner/executor.c
> @@ -24,6 +24,7 @@
>
> #include "igt_aux.h"
> #include "igt_core.h"
> +#include "igt_taints.h"
> #include "executor.h"
> #include "output_strings.h"
>
> @@ -307,70 +308,23 @@ static char *handle_lockdep(void)
> return NULL;
> }
>
> -/* see Linux's include/linux/kernel.h */
> -static const struct {
> - unsigned long bit;
> - const char *explanation;
> -} abort_taints[] = {
> - {(1 << 5), "TAINT_BAD_PAGE: Bad page reference or an unexpected page flags."},
> - {(1 << 7), "TAINT_DIE: Kernel has died - BUG/OOPS."},
> - {(1 << 9), "TAINT_WARN: WARN_ON has happened."},
> - {0, 0}};
> -
> -static unsigned long bad_taints(void)
> -{
> - static unsigned long __bad_taints;
> -
> - if (!__bad_taints) {
> - for (typeof(*abort_taints) *taint = abort_taints;
> - taint->bit;
> - taint++)
> - __bad_taints |= taint->bit;
> - }
> -
> - return __bad_taints;
> -}
> -
> -static unsigned long is_tainted(unsigned long taints)
> -{
> - return taints & bad_taints();
> -}
> -
> -static unsigned long tainted(unsigned long *taints)
> -{
> - FILE *f;
> -
> - *taints = 0;
> -
> - f = fopen("/proc/sys/kernel/tainted", "r");
> - if (f) {
> - fscanf(f, "%lu", taints);
> - fclose(f);
> - }
> -
> - return is_tainted(*taints);
> -}
> -
> static char *handle_taint(void)
> {
> - unsigned long taints;
> + unsigned long taints, bad;
> + char *explain;
> char *reason;
>
> - if (!tainted(&taints))
> + bad = igt_kernel_tainted(&taints);
> + if (!bad)
> return NULL;
>
> - asprintf(&reason, "Kernel badly tainted (%#lx) (check dmesg for details):\n",
> - taints);
> -
> - for (typeof(*abort_taints) *taint = abort_taints; taint->bit; taint++) {
> - if (taint->bit & taints) {
> - char *old_reason = reason;
> - asprintf(&reason, "%s\t(%#lx) %s\n",
> - old_reason,
> - taint->bit,
> - taint->explanation);
> - free(old_reason);
> - }
> + asprintf(&reason, "Kernel badly tainted (%#lx, %#lx) (check dmesg for details):\n",
> + taints, bad);
> +
> + while ((explain = igt_explain_taints(&bad))) {
> + char *old_reason = reason;
> + asprintf(&reason, "%s\t%s\n", old_reason, explain);
> + free(old_reason);
> }
>
> return reason;
> @@ -1142,7 +1096,8 @@ static int monitor_output(pid_t child,
> sigfd = -1; /* we are dying, no signal handling for now */
> }
>
> - timeout_reason = need_to_timeout(settings, killed, tainted(&taints),
> + timeout_reason = need_to_timeout(settings, killed,
> + igt_kernel_tainted(&taints),
> igt_time_elapsed(&time_last_activity, &time_now),
> igt_time_elapsed(&time_last_subtest, &time_now),
> igt_time_elapsed(&time_killed, &time_now),
> --
> 2.30.0
>
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