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From:   Po-Hsu Lin <po-hsu.lin@canonical.com>
To:     stable@vger.kernel.org, gregkh@linuxfoundation.org
Cc:     memxor@gmail.com, linux-kernel@vger.kernel.org, ast@kernel.org,
        daniel@iogearbox.net, andrii@kernel.org, kafai@fb.com,
        songliubraving@fb.com, yhs@fb.com, john.fastabend@gmail.com,
        kpsingh@kernel.org, shuah@kernel.org, bpf@vger.kernel.org,
        po-hsu.lin@canonical.com
Subject: [PATCH stable 5.15 1/1] Revert "selftests/bpf: Add test for bpf_timer overwriting crash"
Date:   Thu,  7 Jul 2022 17:42:07 +0800
Message-Id: <20220707094207.229875-2-po-hsu.lin@canonical.com>
In-Reply-To: <20220707094207.229875-1-po-hsu.lin@canonical.com>
References: <20220707094207.229875-1-po-hsu.lin@canonical.com>
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This reverts commit b0028e1cc1faf2e5d88ad4065590aca90d650182 which is
commit a7e75016a0753c24d6c995bc02501ae35368e333 upstream.

It will break the bpf self-tests build with:
progs/timer_crash.c:8:19: error: field has incomplete type 'struct bpf_timer'
        struct bpf_timer timer;
                         ^
/home/ubuntu/linux/tools/testing/selftests/bpf/tools/include/bpf/bpf_helper_defs.h:39:8:
note: forward declaration of 'struct bpf_timer'
struct bpf_timer;
       ^
1 error generated.

This test can only be built with 5.17 and newer kernels.

Signed-off-by: Po-Hsu Lin <po-hsu.lin@canonical.com>
---
 .../testing/selftests/bpf/prog_tests/timer_crash.c | 32 -------------
 tools/testing/selftests/bpf/progs/timer_crash.c    | 54 ----------------------
 2 files changed, 86 deletions(-)
 delete mode 100644 tools/testing/selftests/bpf/prog_tests/timer_crash.c
 delete mode 100644 tools/testing/selftests/bpf/progs/timer_crash.c

diff --git a/tools/testing/selftests/bpf/prog_tests/timer_crash.c b/tools/testing/selftests/bpf/prog_tests/timer_crash.c
deleted file mode 100644
index f74b823..00000000
--- a/tools/testing/selftests/bpf/prog_tests/timer_crash.c
+++ /dev/null
@@ -1,32 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-#include <test_progs.h>
-#include "timer_crash.skel.h"
-
-enum {
-	MODE_ARRAY,
-	MODE_HASH,
-};
-
-static void test_timer_crash_mode(int mode)
-{
-	struct timer_crash *skel;
-
-	skel = timer_crash__open_and_load();
-	if (!ASSERT_OK_PTR(skel, "timer_crash__open_and_load"))
-		return;
-	skel->bss->pid = getpid();
-	skel->bss->crash_map = mode;
-	if (!ASSERT_OK(timer_crash__attach(skel), "timer_crash__attach"))
-		goto end;
-	usleep(1);
-end:
-	timer_crash__destroy(skel);
-}
-
-void test_timer_crash(void)
-{
-	if (test__start_subtest("array"))
-		test_timer_crash_mode(MODE_ARRAY);
-	if (test__start_subtest("hash"))
-		test_timer_crash_mode(MODE_HASH);
-}
diff --git a/tools/testing/selftests/bpf/progs/timer_crash.c b/tools/testing/selftests/bpf/progs/timer_crash.c
deleted file mode 100644
index f8f7944..00000000
--- a/tools/testing/selftests/bpf/progs/timer_crash.c
+++ /dev/null
@@ -1,54 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-
-#include <vmlinux.h>
-#include <bpf/bpf_tracing.h>
-#include <bpf/bpf_helpers.h>
-
-struct map_elem {
-	struct bpf_timer timer;
-	struct bpf_spin_lock lock;
-};
-
-struct {
-	__uint(type, BPF_MAP_TYPE_ARRAY);
-	__uint(max_entries, 1);
-	__type(key, int);
-	__type(value, struct map_elem);
-} amap SEC(".maps");
-
-struct {
-	__uint(type, BPF_MAP_TYPE_HASH);
-	__uint(max_entries, 1);
-	__type(key, int);
-	__type(value, struct map_elem);
-} hmap SEC(".maps");
-
-int pid = 0;
-int crash_map = 0; /* 0 for amap, 1 for hmap */
-
-SEC("fentry/do_nanosleep")
-int sys_enter(void *ctx)
-{
-	struct map_elem *e, value = {};
-	void *map = crash_map ? (void *)&hmap : (void *)&amap;
-
-	if (bpf_get_current_task_btf()->tgid != pid)
-		return 0;
-
-	*(void **)&value = (void *)0xdeadcaf3;
-
-	bpf_map_update_elem(map, &(int){0}, &value, 0);
-	/* For array map, doing bpf_map_update_elem will do a
-	 * check_and_free_timer_in_array, which will trigger the crash if timer
-	 * pointer was overwritten, for hmap we need to use bpf_timer_cancel.
-	 */
-	if (crash_map == 1) {
-		e = bpf_map_lookup_elem(map, &(int){0});
-		if (!e)
-			return 0;
-		bpf_timer_cancel(&e->timer);
-	}
-	return 0;
-}
-
-char _license[] SEC("license") = "GPL";
-- 
2.7.4