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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Geliang Tang <geliang.tang@suse.com>,
        Tommi Rantala <tommi.t.rantala@nokia.com>,
        Kumar Kartikeya Dwivedi <memxor@gmail.com>,
        Alexei Starovoitov <ast@kernel.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.4 17/17] Revert "selftests/bpf: Add test for bpf_timer overwriting crash"
Date:   Mon, 21 Mar 2022 14:52:53 +0100
Message-Id: <20220321133217.653517515@linuxfoundation.org>
In-Reply-To: <20220321133217.148831184@linuxfoundation.org>
References: <20220321133217.148831184@linuxfoundation.org>
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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This reverts commit dcf55b071de9231e197ba7b1a2d0a423e8d7d33a which is
commit a7e75016a0753c24d6c995bc02501ae35368e333 upstream.

It is reported to break the bpf self-tests.

Reported-by: Geliang Tang <geliang.tang@suse.com>
Reported-by: Tommi Rantala <tommi.t.rantala@nokia.com>
Cc: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220209070324.1093182-3-memxor@gmail.com
Cc: Sasha Levin <sashal@kernel.org>
Link: https://lore.kernel.org/r/a0a7298ca5c64b3d0ecfcc8821c2de79186fa9f7.camel@nokia.com
Link: https://lore.kernel.org/r/HE1PR0402MB3497CB13A12C4D15D20A1FCCF8139@HE1PR0402MB3497.eurprd04.prod.outlook.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 tools/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

--- 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);
-}
--- 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";