Re: [PATCH net-next 02/19] lib: add tests for reference tracker
flat view
From: Eric Dumazet <hidden>
Date: 2021-12-02 03:31:18
On Wed, Dec 1, 2021 at 7:21 PM Eric Dumazet [off-list ref] wrote:
From: Eric Dumazet <redacted> This module uses reference tracker, forcing two issues. 1) Double free of a tracker 2) leak of two trackers, one being allocated from softirq context. "modprobe test_ref_tracker" would emit the following traces. (Use scripts/decode_stacktrace.sh if necessary) [
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Signed-off-by: Eric Dumazet <redacted> --- lib/Kconfig.debug | 10 ++++ lib/Makefile | 2 +- lib/test_ref_tracker.c | 116 +++++++++++++++++++++++++++++++++++++++++ 3 files changed, 127 insertions(+), 1 deletion(-) create mode 100644 lib/test_ref_tracker.cdiff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 5c12bde10996cf97b5f075d318089b1be73f71d7..d005f555872147e15d3e0a65d2a03e1a5c44f5f0 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug@@ -2106,6 +2106,16 @@ config BACKTRACE_SELF_TEST Say N if you are unsure. +config TEST_REF_TRACKER + tristate "Self test for reference tracker" + depends on DEBUG_KERNEL + select REF_TRACKER + help + This option provides a kernel module performing tests + using reference tracker infrastructure. + + Say N if you are unsure. + config RBTREE_TEST tristate "Red-Black tree test" depends on DEBUG_KERNELdiff --git a/lib/Makefile b/lib/Makefile index c1fd9243ddb9cc1ac5252d7eb8009f9290782c4a..b213a7bbf3fda2eb9f234fb7473b8f1b617bed6b 100644 --- a/lib/Makefile +++ b/lib/Makefile@@ -101,7 +101,7 @@ obj-$(CONFIG_TEST_LOCKUP) += test_lockup.o obj-$(CONFIG_TEST_HMM) += test_hmm.o obj-$(CONFIG_TEST_FREE_PAGES) += test_free_pages.o obj-$(CONFIG_KPROBES_SANITY_TEST) += test_kprobes.o - +obj-$(CONFIG_TEST_REF_TRACKER) += test_ref_tracker.o # # CFLAGS for compiling floating point code inside the kernel. x86/Makefile turns # off the generation of FPU/SSE* instructions for kernel proper but FPU_FLAGSdiff --git a/lib/test_ref_tracker.c b/lib/test_ref_tracker.c new file mode 100644 index 0000000000000000000000000000000000000000..73bf9255e03790fa50491fe8e5cd411d54827c45 --- /dev/null +++ b/lib/test_ref_tracker.c@@ -0,0 +1,116 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Referrence tracker self test. + * + * Copyright (c) 2021 Eric Dumazet <edumazet@google.com> + */ +#include <linux/init.h> +#include <linux/module.h> +#include <linux/delay.h> +#include <linux/ref_tracker.h> +#include <linux/slab.h> +#include <linux/timer.h> + +static struct ref_tracker_dir ref_dir; +static struct ref_tracker *tracker[20]; + +#define TRT_ALLOC(X) static noinline void \ + alloctest_ref_tracker_alloc##X(struct ref_tracker_dir *dir, \ + struct ref_tracker **trackerp) \ + { \ + ref_tracker_alloc(dir, trackerp, GFP_KERNEL); \ + } + +TRT_ALLOC(0) +TRT_ALLOC(1) +TRT_ALLOC(2) +TRT_ALLOC(3) +TRT_ALLOC(4) +TRT_ALLOC(5) +TRT_ALLOC(6) +TRT_ALLOC(7) +TRT_ALLOC(8) +TRT_ALLOC(9) +TRT_ALLOC(10) +TRT_ALLOC(11) +TRT_ALLOC(12) +TRT_ALLOC(13) +TRT_ALLOC(14) +TRT_ALLOC(15) +TRT_ALLOC(16) +TRT_ALLOC(17) +TRT_ALLOC(18) +TRT_ALLOC(19) + +#undef TRT_ALLOC + +static noinline void +alloctest_ref_tracker_free(struct ref_tracker_dir *dir, + struct ref_tracker **trackerp) +{ + ref_tracker_free(dir, trackerp); +} + + +static struct timer_list test_ref_tracker_timer; +static atomic_t test_ref_timer_done = ATOMIC_INIT(0); + +static void test_ref_tracker_timer_func(struct timer_list *t) +{ + alloctest_ref_tracker_alloc0(&ref_dir, &tracker[0]);
This will be changed to use GFP_ATOMIC instead of GFP_KERNEL
ref_tracker_alloc(&ref_dir, ..., GFP_ATOMIC);
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+ atomic_set(&test_ref_timer_done, 1); +} +