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authorYafang Shao2023-05-15 13:08:48 +0000
committerGreg Kroah-Hartman2023-07-19 16:21:05 +0200
commit8ea165e1f89d7ddd9a16046809013f9792bb33c3 (patch)
tree52884f4293d27a8cf2c0106046451c05a0aaa0ec
parent1949721c741b5fc966b6a981ab965b04f708d1f9 (diff)
bpf: Remove bpf trampoline selector
[ Upstream commit 47e79cbeea4b3891ad476047f4c68543eb51c8e0 ] After commit e21aa341785c ("bpf: Fix fexit trampoline."), the selector is only used to indicate how many times the bpf trampoline image are updated and been displayed in the trampoline ksym name. After the trampoline is freed, the selector will start from 0 again. So the selector is a useless value to the user. We can remove it. If the user want to check whether the bpf trampoline image has been updated or not, the user can compare the address. Each time the trampoline image is updated, the address will change consequently. Jiri also pointed out another issue that perf is still using the old name "bpf_trampoline_%lu", so this change can fix the issue in perf. Fixes: e21aa341785c ("bpf: Fix fexit trampoline.") Signed-off-by: Yafang Shao <laoar.shao@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Song Liu <song@kernel.org> Cc: Jiri Olsa <olsajiri@gmail.com> Link: https://lore.kernel.org/bpf/ZFvOOlrmHiY9AgXE@krava Link: https://lore.kernel.org/bpf/20230515130849.57502-3-laoar.shao@gmail.com Signed-off-by: Sasha Levin <sashal@kernel.org>
-rw-r--r--include/linux/bpf.h1
-rw-r--r--kernel/bpf/trampoline.c11
2 files changed, 4 insertions, 8 deletions
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 942f9ac9fa7b..8cef9ec3a89c 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -933,7 +933,6 @@ struct bpf_trampoline {
int progs_cnt[BPF_TRAMP_MAX];
/* Executable image of trampoline */
struct bpf_tramp_image *cur_image;
- u64 selector;
struct module *mod;
};
diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c
index f1504cb5b6e1..91d8de938a3d 100644
--- a/kernel/bpf/trampoline.c
+++ b/kernel/bpf/trampoline.c
@@ -372,7 +372,7 @@ static void bpf_tramp_image_put(struct bpf_tramp_image *im)
call_rcu_tasks_trace(&im->rcu, __bpf_tramp_image_put_rcu_tasks);
}
-static struct bpf_tramp_image *bpf_tramp_image_alloc(u64 key, u32 idx)
+static struct bpf_tramp_image *bpf_tramp_image_alloc(u64 key)
{
struct bpf_tramp_image *im;
struct bpf_ksym *ksym;
@@ -399,7 +399,7 @@ static struct bpf_tramp_image *bpf_tramp_image_alloc(u64 key, u32 idx)
ksym = &im->ksym;
INIT_LIST_HEAD_RCU(&ksym->lnode);
- snprintf(ksym->name, KSYM_NAME_LEN, "bpf_trampoline_%llu_%u", key, idx);
+ snprintf(ksym->name, KSYM_NAME_LEN, "bpf_trampoline_%llu", key);
bpf_image_ksym_add(image, ksym);
return im;
@@ -429,11 +429,10 @@ static int bpf_trampoline_update(struct bpf_trampoline *tr, bool lock_direct_mut
err = unregister_fentry(tr, tr->cur_image->image);
bpf_tramp_image_put(tr->cur_image);
tr->cur_image = NULL;
- tr->selector = 0;
goto out;
}
- im = bpf_tramp_image_alloc(tr->key, tr->selector);
+ im = bpf_tramp_image_alloc(tr->key);
if (IS_ERR(im)) {
err = PTR_ERR(im);
goto out;
@@ -471,8 +470,7 @@ again:
set_memory_ro((long)im->image, 1);
set_memory_x((long)im->image, 1);
- WARN_ON(tr->cur_image && tr->selector == 0);
- WARN_ON(!tr->cur_image && tr->selector);
+ WARN_ON(tr->cur_image && total == 0);
if (tr->cur_image)
/* progs already running at this address */
err = modify_fentry(tr, tr->cur_image->image, im->image, lock_direct_mutex);
@@ -502,7 +500,6 @@ again:
if (tr->cur_image)
bpf_tramp_image_put(tr->cur_image);
tr->cur_image = im;
- tr->selector++;
out:
/* If any error happens, restore previous flags */
if (err)