LoongArch: BPF: Fix incorrect return pointer value in the eBPF program #9496
+23
−2
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
![kernel-patches-daemon-bpf[bot]](https://avatars.githubusercontent.com/u/70728002?s=60&v=4){kind=small}
|
Upstream branch: 0786654 |
kernel-patches-daemon-bpf
bot
force-pushed
the
bpf-next_base
branch
from
c210f22 to
2530e45
Compare
|
Upstream branch: dc0fe95 |
kernel-patches-daemon-bpf
bot
force-pushed
the
series/991838=>bpf-next
branch
from
e00235c to
f6abc20
Compare
kernel-patches-daemon-bpf
bot
force-pushed
the
bpf-next_base
branch
from
2530e45 to
61c9cef
Compare
|
Upstream branch: c80d797 |
kernel-patches-daemon-bpf
bot
force-pushed
the
series/991838=>bpf-next
branch
from
f6abc20 to
d1dc9a9
Compare
kernel-patches-daemon-bpf
bot
force-pushed
the
bpf-next_base
branch
from
61c9cef to
715d6cb
Compare
In some eBPF programs, the return value is a pointer.
When the kernel call an eBPF program (such as struct_ops),
it expects a 64-bit address to be returned, but instead a 32-bit value.
Before applying this patch:
./test_progs -a ns_bpf_qdisc
CPU 7 Unable to handle kernel paging request at virtual
address 0000000010440158.
As shown in the following test case,
bpf_fifo_dequeue return value is a pointer.
progs/bpf_qdisc_fifo.c
SEC("struct_ops/bpf_fifo_dequeue")
struct sk_buff *BPF_PROG(bpf_fifo_dequeue, struct Qdisc *sch)
{
struct sk_buff *skb = NULL;
........
skb = bpf_kptr_xchg(&skbn->skb, skb);
........
return skb;
}
kernel call bpf_fifo_dequeue：
net/sched/sch_generic.c
static struct sk_buff *dequeue_skb(struct Qdisc *q, bool *validate,
int *packets)
{
struct sk_buff *skb = NULL;
........
skb = q->dequeue(q);
.........
}
When accessing the skb, an address exception error will occur.
because the value returned by q->dequeue at this point is a 32-bit
address rather than a 64-bit address.
After applying the patch：
./test_progs -a ns_bpf_qdisc
Warning: sch_htb: quantum of class 10001 is small. Consider r2q change.
213/1 ns_bpf_qdisc/fifo:OK
213/2 ns_bpf_qdisc/fq:OK
213/3 ns_bpf_qdisc/attach to mq:OK
213/4 ns_bpf_qdisc/attach to non root:OK
213/5 ns_bpf_qdisc/incompl_ops:OK
213 ns_bpf_qdisc:OK
Summary: 1/5 PASSED, 0 SKIPPED, 0 FAILED
Fixes: 73c359d ("LoongArch: BPF: Sign-extend return values")
Signed-off-by: Jinyang He <[email protected]>
Signed-off-by: Haoran Jiang <[email protected]>
----------
v2:
1,add emit_slt* helpers
2,Use slt/slld/srad instructions to avoid branch
|
Upstream branch: 3ec8560 |
kernel-patches-daemon-bpf
bot
force-pushed
the
series/991838=>bpf-next
branch
from
d1dc9a9 to
7f891d0
Compare
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Pull request for series with
subject: LoongArch: BPF: Fix incorrect return pointer value in the eBPF program
version: 2
url: https://patchwork.kernel.org/project/netdevbpf/list/?series=991838