Some places calculate the origin_call by checking if
BPF_TRAMP_F_SKIP_FRAME is set. However, it should use
BPF_TRAMP_F_ORIG_STACK for this propose. Just fix them.
Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Acked-by: Alexei Starovoitov <ast@kernel.org>
---
arch/riscv/net/bpf_jit_comp64.c | 2 +-
arch/x86/net/bpf_jit_comp.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/riscv/net/bpf_jit_comp64.c b/arch/riscv/net/bpf_jit_comp64.c
index 45cbc7c6fe49..21c70ae3296b 100644
--- a/arch/riscv/net/bpf_jit_comp64.c
+++ b/arch/riscv/net/bpf_jit_comp64.c
@@ -1131,7 +1131,7 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im,
store_args(nr_arg_slots, args_off, ctx);
/* skip to actual body of traced function */
- if (flags & BPF_TRAMP_F_SKIP_FRAME)
+ if (flags & BPF_TRAMP_F_ORIG_STACK)
orig_call += RV_FENTRY_NINSNS * 4;
if (flags & BPF_TRAMP_F_CALL_ORIG) {
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index 36a0d4db9f68..808d4343f6cf 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -3289,7 +3289,7 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *rw_im
arg_stack_off = stack_size;
- if (flags & BPF_TRAMP_F_SKIP_FRAME) {
+ if (flags & BPF_TRAMP_F_CALL_ORIG) {
/* skip patched call instruction and point orig_call to actual
* body of the kernel function.
*/
--
2.51.2On Nov 18 2025, Menglong Dong wrote: > Some places calculate the origin_call by checking if > BPF_TRAMP_F_SKIP_FRAME is set. However, it should use > BPF_TRAMP_F_ORIG_STACK for this propose. Just fix them. > > Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn> > Acked-by: Alexei Starovoitov <ast@kernel.org> This breaks RISC-V: [ 8.584381][ T1] systemd[1]: bpf-restrict-fs: LSM BPF program attached [ 8.588359][ T1] Insufficient stack space to handle exception! [ 8.588823][ T1] Task stack: [0xff20000000010000..0xff20000000014000] [ 8.589219][ T1] Overflow stack: [0xff600000ffdad070..0xff600000ffdae070] [ 8.590133][ T1] CPU: 1 UID: 0 PID: 1 Comm: systemd Not tainted 6.18.0-rc5+ #15 PREEMPT(voluntary) c900881ed1c1988ec5cf3e914d0edeb1b4d83ca3 [ 8.590898][ T1] Hardware name: riscv-virtio qemu/qemu, BIOS 2025.10 10/01/2025 [ 8.591494][ T1] epc : copy_from_kernel_nofault+0xa/0x198 [ 8.592292][ T1] ra : bpf_probe_read_kernel+0x20/0x60 [ 8.592658][ T1] epc : ffffffff802b732a ra : ffffffff801e6070 sp : ff2000000000ffe0 [ 8.593121][ T1] gp : ffffffff82262ed0 tp : 0000000000000000 t0 : ffffffff80022320 [ 8.593566][ T1] t1 : ffffffff801e6056 t2 : 0000000000000000 s0 : ff20000000010040 [ 8.593997][ T1] s1 : 0000000000000008 a0 : ff20000000010050 a1 : ff60000083b3d320 [ 8.594446][ T1] a2 : 0000000000000008 a3 : 0000000000000097 a4 : 0000000000000000 [ 8.594940][ T1] a5 : 0000000000000000 a6 : 0000000000000021 a7 : 0000000000000003 [ 8.595396][ T1] s2 : ff20000000010050 s3 : ff6000008459fc18 s4 : ff60000083b3d340 [ 8.595831][ T1] s5 : ff20000000010060 s6 : 0000000000000000 s7 : ff20000000013aa8 [ 8.596215][ T1] s8 : 0000000000000000 s9 : 0000000000008000 s10: 000000000058dcb0 [ 8.596641][ T1] s11: 000000000058dca7 t3 : 000000006925116d t4 : ff6000008090f026 [ 8.597065][ T1] t5 : 00007fff9b0cbaa8 t6 : 0000000000000016 [ 8.597363][ T1] status: 0000000200000120 badaddr: 0000000000000000 cause: 8000000000000005 [ 8.598033][ T1] Kernel panic - not syncing: Kernel stack overflow [ 8.598597][ T1] CPU: 1 UID: 0 PID: 1 Comm: systemd Not tainted 6.18.0-rc5+ #15 PREEMPT(voluntary) c900881ed1c1988ec5cf3e914d0edeb1b4d83ca3 [ 8.599244][ T1] Hardware name: riscv-virtio qemu/qemu, BIOS 2025.10 10/01/2025 [ 8.599659][ T1] Call Trace: [ 8.600117][ T1] [<ffffffff8001a1f8>] dump_backtrace+0x28/0x38 [ 8.600517][ T1] [<ffffffff80002502>] show_stack+0x3a/0x50 [ 8.600844][ T1] [<ffffffff800122be>] dump_stack_lvl+0x56/0x80 [ 8.601176][ T1] [<ffffffff80012300>] dump_stack+0x18/0x22 [ 8.601518][ T1] [<ffffffff80002abe>] vpanic+0xf6/0x328 [ 8.601819][ T1] [<ffffffff80002d2e>] panic+0x3e/0x40 [ 8.602088][ T1] [<ffffffff80019ef0>] handle_bad_stack+0x98/0xa0 [ 8.602395][ T1] [<ffffffff801e6070>] bpf_probe_read_kernel+0x20/0x60 -- Andreas Schwab, schwab@linux-m68k.org GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1 "And now for something completely different."
On Thu, Dec 18, 2025 at 10:45 PM Andreas Schwab <schwab@linux-m68k.org> wrote: > > On Nov 18 2025, Menglong Dong wrote: > > > Some places calculate the origin_call by checking if > > BPF_TRAMP_F_SKIP_FRAME is set. However, it should use > > BPF_TRAMP_F_ORIG_STACK for this propose. Just fix them. > > > > Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn> > > Acked-by: Alexei Starovoitov <ast@kernel.org> > > This breaks RISC-V: It's weird, as the 2 flags should be set together all the time in RISC-V. Sorry that I'm already in bed, I'll check it tomorrow morning. Thanks! Menglong Dong > > [ 8.584381][ T1] systemd[1]: bpf-restrict-fs: LSM BPF program attached > [ 8.588359][ T1] Insufficient stack space to handle exception! > [ 8.588823][ T1] Task stack: [0xff20000000010000..0xff20000000014000] > [ 8.589219][ T1] Overflow stack: [0xff600000ffdad070..0xff600000ffdae070] > [ 8.590133][ T1] CPU: 1 UID: 0 PID: 1 Comm: systemd Not tainted 6.18.0-rc5+ #15 PREEMPT(voluntary) c900881ed1c1988ec5cf3e914d0edeb1b4d83ca3 > [ 8.590898][ T1] Hardware name: riscv-virtio qemu/qemu, BIOS 2025.10 10/01/2025 > [ 8.591494][ T1] epc : copy_from_kernel_nofault+0xa/0x198 > [ 8.592292][ T1] ra : bpf_probe_read_kernel+0x20/0x60 > [ 8.592658][ T1] epc : ffffffff802b732a ra : ffffffff801e6070 sp : ff2000000000ffe0 > [ 8.593121][ T1] gp : ffffffff82262ed0 tp : 0000000000000000 t0 : ffffffff80022320 > [ 8.593566][ T1] t1 : ffffffff801e6056 t2 : 0000000000000000 s0 : ff20000000010040 > [ 8.593997][ T1] s1 : 0000000000000008 a0 : ff20000000010050 a1 : ff60000083b3d320 > [ 8.594446][ T1] a2 : 0000000000000008 a3 : 0000000000000097 a4 : 0000000000000000 > [ 8.594940][ T1] a5 : 0000000000000000 a6 : 0000000000000021 a7 : 0000000000000003 > [ 8.595396][ T1] s2 : ff20000000010050 s3 : ff6000008459fc18 s4 : ff60000083b3d340 > [ 8.595831][ T1] s5 : ff20000000010060 s6 : 0000000000000000 s7 : ff20000000013aa8 > [ 8.596215][ T1] s8 : 0000000000000000 s9 : 0000000000008000 s10: 000000000058dcb0 > [ 8.596641][ T1] s11: 000000000058dca7 t3 : 000000006925116d t4 : ff6000008090f026 > [ 8.597065][ T1] t5 : 00007fff9b0cbaa8 t6 : 0000000000000016 > [ 8.597363][ T1] status: 0000000200000120 badaddr: 0000000000000000 cause: 8000000000000005 > [ 8.598033][ T1] Kernel panic - not syncing: Kernel stack overflow > [ 8.598597][ T1] CPU: 1 UID: 0 PID: 1 Comm: systemd Not tainted 6.18.0-rc5+ #15 PREEMPT(voluntary) c900881ed1c1988ec5cf3e914d0edeb1b4d83ca3 > [ 8.599244][ T1] Hardware name: riscv-virtio qemu/qemu, BIOS 2025.10 10/01/2025 > [ 8.599659][ T1] Call Trace: > [ 8.600117][ T1] [<ffffffff8001a1f8>] dump_backtrace+0x28/0x38 > [ 8.600517][ T1] [<ffffffff80002502>] show_stack+0x3a/0x50 > [ 8.600844][ T1] [<ffffffff800122be>] dump_stack_lvl+0x56/0x80 > [ 8.601176][ T1] [<ffffffff80012300>] dump_stack+0x18/0x22 > [ 8.601518][ T1] [<ffffffff80002abe>] vpanic+0xf6/0x328 > [ 8.601819][ T1] [<ffffffff80002d2e>] panic+0x3e/0x40 > [ 8.602088][ T1] [<ffffffff80019ef0>] handle_bad_stack+0x98/0xa0 > [ 8.602395][ T1] [<ffffffff801e6070>] bpf_probe_read_kernel+0x20/0x60 > > -- > Andreas Schwab, schwab@linux-m68k.org > GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1 > "And now for something completely different."
On 2025/12/18 22:45 Andreas Schwab <schwab@linux-m68k.org> write: > On Nov 18 2025, Menglong Dong wrote: > > > Some places calculate the origin_call by checking if > > BPF_TRAMP_F_SKIP_FRAME is set. However, it should use > > BPF_TRAMP_F_ORIG_STACK for this propose. Just fix them. > > > > Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn> > > Acked-by: Alexei Starovoitov <ast@kernel.org> > > This breaks RISC-V: Hi, Andreas. Can you offer more information here? After my analysis, I didn't see the problem. BPF_TRAMP_F_SKIP_FRAME and BPF_TRAMP_F_ORIG_STACK are set together all the time in RISC-V, so I changed BPF_TRAMP_F_SKIP_FRAME to BPF_TRAMP_F_ORIG_STACK *should* have no influence. Thanks! Menglong Dong > > [ 8.584381][ T1] systemd[1]: bpf-restrict-fs: LSM BPF program attached > [ 8.588359][ T1] Insufficient stack space to handle exception! > [ 8.588823][ T1] Task stack: [0xff20000000010000..0xff20000000014000] > [ 8.589219][ T1] Overflow stack: [0xff600000ffdad070..0xff600000ffdae070] > [ 8.590133][ T1] CPU: 1 UID: 0 PID: 1 Comm: systemd Not tainted 6.18.0-rc5+ #15 PREEMPT(voluntary) c900881ed1c1988ec5cf3e914d0edeb1b4d83ca3 > [ 8.590898][ T1] Hardware name: riscv-virtio qemu/qemu, BIOS 2025.10 10/01/2025 > [ 8.591494][ T1] epc : copy_from_kernel_nofault+0xa/0x198 > [ 8.592292][ T1] ra : bpf_probe_read_kernel+0x20/0x60 > [ 8.592658][ T1] epc : ffffffff802b732a ra : ffffffff801e6070 sp : ff2000000000ffe0 > [ 8.593121][ T1] gp : ffffffff82262ed0 tp : 0000000000000000 t0 : ffffffff80022320 > [ 8.593566][ T1] t1 : ffffffff801e6056 t2 : 0000000000000000 s0 : ff20000000010040 > [ 8.593997][ T1] s1 : 0000000000000008 a0 : ff20000000010050 a1 : ff60000083b3d320 > [ 8.594446][ T1] a2 : 0000000000000008 a3 : 0000000000000097 a4 : 0000000000000000 > [ 8.594940][ T1] a5 : 0000000000000000 a6 : 0000000000000021 a7 : 0000000000000003 > [ 8.595396][ T1] s2 : ff20000000010050 s3 : ff6000008459fc18 s4 : ff60000083b3d340 > [ 8.595831][ T1] s5 : ff20000000010060 s6 : 0000000000000000 s7 : ff20000000013aa8 > [ 8.596215][ T1] s8 : 0000000000000000 s9 : 0000000000008000 s10: 000000000058dcb0 > [ 8.596641][ T1] s11: 000000000058dca7 t3 : 000000006925116d t4 : ff6000008090f026 > [ 8.597065][ T1] t5 : 00007fff9b0cbaa8 t6 : 0000000000000016 > [ 8.597363][ T1] status: 0000000200000120 badaddr: 0000000000000000 cause: 8000000000000005 > [ 8.598033][ T1] Kernel panic - not syncing: Kernel stack overflow > [ 8.598597][ T1] CPU: 1 UID: 0 PID: 1 Comm: systemd Not tainted 6.18.0-rc5+ #15 PREEMPT(voluntary) c900881ed1c1988ec5cf3e914d0edeb1b4d83ca3 > [ 8.599244][ T1] Hardware name: riscv-virtio qemu/qemu, BIOS 2025.10 10/01/2025 > [ 8.599659][ T1] Call Trace: > [ 8.600117][ T1] [<ffffffff8001a1f8>] dump_backtrace+0x28/0x38 > [ 8.600517][ T1] [<ffffffff80002502>] show_stack+0x3a/0x50 > [ 8.600844][ T1] [<ffffffff800122be>] dump_stack_lvl+0x56/0x80 > [ 8.601176][ T1] [<ffffffff80012300>] dump_stack+0x18/0x22 > [ 8.601518][ T1] [<ffffffff80002abe>] vpanic+0xf6/0x328 > [ 8.601819][ T1] [<ffffffff80002d2e>] panic+0x3e/0x40 > [ 8.602088][ T1] [<ffffffff80019ef0>] handle_bad_stack+0x98/0xa0 > [ 8.602395][ T1] [<ffffffff801e6070>] bpf_probe_read_kernel+0x20/0x60 > > -- > Andreas Schwab, schwab@linux-m68k.org > GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1 > "And now for something completely different." > >
On Dez 19 2025, Menglong Dong wrote: > BPF_TRAMP_F_ORIG_STACK How can that ever be set? if (flags & (BPF_TRAMP_F_ORIG_STACK | BPF_TRAMP_F_SHARE_IPMODIFY)) return -ENOTSUPP; -- Andreas Schwab, schwab@linux-m68k.org GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1 "And now for something completely different."
On 2025/12/19 19:41, Andreas Schwab wrote: > On Dez 19 2025, Menglong Dong wrote: > > > BPF_TRAMP_F_ORIG_STACK > > How can that ever be set? Oops, my bad! It should be BPF_TRAMP_F_CALL_ORIG here. I think it is some kind of copy-paste mistake. I'll send a fix for it. Thanks! Menglong Dong > > if (flags & (BPF_TRAMP_F_ORIG_STACK | BPF_TRAMP_F_SHARE_IPMODIFY)) > return -ENOTSUPP; > >
On 2025/12/19 20:27, Menglong Dong wrote:
> On 2025/12/19 19:41, Andreas Schwab wrote:
> > On Dez 19 2025, Menglong Dong wrote:
> >
> > > BPF_TRAMP_F_ORIG_STACK
> >
> > How can that ever be set?
>
> Oops, my bad! It should be BPF_TRAMP_F_CALL_ORIG here. I think
> it is some kind of copy-paste mistake. I'll send a fix for it.
I sent the following patch twice, but I didn't see it in the
mail list. I suspect there is something wrong with my gmail.
Hi, Alexei. Can you see my patch?
-->patch<--
From 5dbae5dcba3aa7fa10e506e9fd1a28a6802d9b00 Mon Sep 17 00:00:00 2001
From: Menglong Dong <dongml2@chinatelecom.cn>
Date: Fri, 19 Dec 2025 20:33:10 +0800
Subject: [PATCH RESEND bpf] riscv, bpf: fix incorrect usage of BPF_TRAMP_F_ORIG_STACK
The usage of BPF_TRAMP_F_ORIG_STACK in __arch_prepare_bpf_trampoline() is
wrong, and it should be BPF_TRAMP_F_CALL_ORIG, which caused crash as
Andreas reported:
Insufficient stack space to handle exception!
Task stack: [0xff20000000010000..0xff20000000014000]
Overflow stack: [0xff600000ffdad070..0xff600000ffdae070]
CPU: 1 UID: 0 PID: 1 Comm: systemd Not tainted 6.18.0-rc5+ #15 PREEMPT(voluntary)
Hardware name: riscv-virtio qemu/qemu, BIOS 2025.10 10/01/2025
epc : copy_from_kernel_nofault+0xa/0x198
ra : bpf_probe_read_kernel+0x20/0x60
epc : ffffffff802b732a ra : ffffffff801e6070 sp : ff2000000000ffe0
gp : ffffffff82262ed0 tp : 0000000000000000 t0 : ffffffff80022320
t1 : ffffffff801e6056 t2 : 0000000000000000 s0 : ff20000000010040
s1 : 0000000000000008 a0 : ff20000000010050 a1 : ff60000083b3d320
a2 : 0000000000000008 a3 : 0000000000000097 a4 : 0000000000000000
a5 : 0000000000000000 a6 : 0000000000000021 a7 : 0000000000000003
s2 : ff20000000010050 s3 : ff6000008459fc18 s4 : ff60000083b3d340
s5 : ff20000000010060 s6 : 0000000000000000 s7 : ff20000000013aa8
s8 : 0000000000000000 s9 : 0000000000008000 s10: 000000000058dcb0
s11: 000000000058dca7 t3 : 000000006925116d t4 : ff6000008090f026
t5 : 00007fff9b0cbaa8 t6 : 0000000000000016
status: 0000000200000120 badaddr: 0000000000000000 cause: 8000000000000005
Kernel panic - not syncing: Kernel stack overflow
CPU: 1 UID: 0 PID: 1 Comm: systemd Not tainted 6.18.0-rc5+ #15 PREEMPT(voluntary)
Hardware name: riscv-virtio qemu/qemu, BIOS 2025.10 10/01/2025
Call Trace:
[<ffffffff8001a1f8>] dump_backtrace+0x28/0x38
[<ffffffff80002502>] show_stack+0x3a/0x50
[<ffffffff800122be>] dump_stack_lvl+0x56/0x80
[<ffffffff80012300>] dump_stack+0x18/0x22
[<ffffffff80002abe>] vpanic+0xf6/0x328
[<ffffffff80002d2e>] panic+0x3e/0x40
[<ffffffff80019ef0>] handle_bad_stack+0x98/0xa0
[<ffffffff801e6070>] bpf_probe_read_kernel+0x20/0x60
Just fix it.
Fixes: 47c9214dcbea ("bpf: fix the usage of BPF_TRAMP_F_SKIP_FRAME")
Reported-by: Andreas Schwab <schwab@linux-m68k.org>
Closes: https://lore.kernel.org/bpf/874ipnkfvt.fsf@igel.home/
Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
---
arch/riscv/net/bpf_jit_comp64.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/riscv/net/bpf_jit_comp64.c b/arch/riscv/net/bpf_jit_comp64.c
index 5f9457e910e8..09b70bf362d3 100644
--- a/arch/riscv/net/bpf_jit_comp64.c
+++ b/arch/riscv/net/bpf_jit_comp64.c
@@ -1134,7 +1134,7 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im,
store_args(nr_arg_slots, args_off, ctx);
/* skip to actual body of traced function */
- if (flags & BPF_TRAMP_F_ORIG_STACK)
+ if (flags & BPF_TRAMP_F_CALL_ORIG)
orig_call += RV_FENTRY_NINSNS * 4;
if (flags & BPF_TRAMP_F_CALL_ORIG) {
--
2.52.0
--<patch>--
>
> Thanks!
> Menglong Dong
>
> >
> > if (flags & (BPF_TRAMP_F_ORIG_STACK | BPF_TRAMP_F_SHARE_IPMODIFY))
> > return -ENOTSUPP;
> >
> >
>
>
>
>
>
>On Dez 19 2025, Menglong Dong wrote: > diff --git a/arch/riscv/net/bpf_jit_comp64.c b/arch/riscv/net/bpf_jit_comp64.c > index 5f9457e910e8..09b70bf362d3 100644 > --- a/arch/riscv/net/bpf_jit_comp64.c > +++ b/arch/riscv/net/bpf_jit_comp64.c > @@ -1134,7 +1134,7 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, > store_args(nr_arg_slots, args_off, ctx); > > /* skip to actual body of traced function */ > - if (flags & BPF_TRAMP_F_ORIG_STACK) > + if (flags & BPF_TRAMP_F_CALL_ORIG) > orig_call += RV_FENTRY_NINSNS * 4; There are now three occurrences of that condition, and only the third one uses orig_call. How about merging them? -- Andreas Schwab, schwab@linux-m68k.org GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1 "And now for something completely different."
On Fri, Dec 19, 2025 at 9:49 PM Andreas Schwab <schwab@linux-m68k.org> wrote:
>
> On Dez 19 2025, Menglong Dong wrote:
>
> > diff --git a/arch/riscv/net/bpf_jit_comp64.c b/arch/riscv/net/bpf_jit_comp64.c
> > index 5f9457e910e8..09b70bf362d3 100644
> > --- a/arch/riscv/net/bpf_jit_comp64.c
> > +++ b/arch/riscv/net/bpf_jit_comp64.c
> > @@ -1134,7 +1134,7 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im,
> > store_args(nr_arg_slots, args_off, ctx);
> >
> > /* skip to actual body of traced function */
> > - if (flags & BPF_TRAMP_F_ORIG_STACK)
> > + if (flags & BPF_TRAMP_F_CALL_ORIG)
> > orig_call += RV_FENTRY_NINSNS * 4;
>
> There are now three occurrences of that condition, and only the third
> one uses orig_call. How about merging them?
Yeah, I think we can merge it to the third one, like this:
diff --git a/arch/riscv/net/bpf_jit_comp64.c b/arch/riscv/net/bpf_jit_comp64.c
index 5f9457e910e8..37888abee70c 100644
--- a/arch/riscv/net/bpf_jit_comp64.c
+++ b/arch/riscv/net/bpf_jit_comp64.c
@@ -1133,10 +1133,6 @@ static int __arch_prepare_bpf_trampoline(struct
bpf_tramp_image *im,
store_args(nr_arg_slots, args_off, ctx);
- /* skip to actual body of traced function */
- if (flags & BPF_TRAMP_F_ORIG_STACK)
- orig_call += RV_FENTRY_NINSNS * 4;
-
if (flags & BPF_TRAMP_F_CALL_ORIG) {
emit_imm(RV_REG_A0, ctx->insns ? (const s64)im :
RV_MAX_COUNT_IMM, ctx);
ret = emit_call((const u64)__bpf_tramp_enter, true, ctx);
@@ -1171,6 +1167,8 @@ static int __arch_prepare_bpf_trampoline(struct
bpf_tramp_image *im,
}
if (flags & BPF_TRAMP_F_CALL_ORIG) {
+ /* skip to actual body of traced function */
+ orig_call += RV_FENTRY_NINSNS * 4;
restore_args(min_t(int, nr_arg_slots,
RV_MAX_REG_ARGS), args_off, ctx);
restore_stack_args(nr_arg_slots - RV_MAX_REG_ARGS,
args_off, stk_arg_off, ctx);
ret = emit_call((const u64)orig_call, true, ctx);
>
> --
> Andreas Schwab, schwab@linux-m68k.org
> GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1
> "And now for something completely different."
On Dez 19 2025, Menglong Dong wrote:
> @@ -1171,6 +1167,8 @@ static int __arch_prepare_bpf_trampoline(struct
> bpf_tramp_image *im,
> }
>
> if (flags & BPF_TRAMP_F_CALL_ORIG) {
> + /* skip to actual body of traced function */
> + orig_call += RV_FENTRY_NINSNS * 4;
Before this line, orig_call still contains the same value as func_addr,
with the latter being dead, so there is not much point in using a copy.
--
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1
"And now for something completely different."
On Fri, Dec 19, 2025 at 10:50 PM Andreas Schwab <schwab@linux-m68k.org> wrote:
>
> On Dez 19 2025, Menglong Dong wrote:
>
> > @@ -1171,6 +1167,8 @@ static int __arch_prepare_bpf_trampoline(struct
> > bpf_tramp_image *im,
> > }
> >
> > if (flags & BPF_TRAMP_F_CALL_ORIG) {
> > + /* skip to actual body of traced function */
> > + orig_call += RV_FENTRY_NINSNS * 4;
>
> Before this line, orig_call still contains the same value as func_addr,
> with the latter being dead, so there is not much point in using a copy.
Yeah, we can use "func_addr + RV_FENTRY_NINSNS * 4" here directly.
>
> --
> Andreas Schwab, schwab@linux-m68k.org
> GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1
> "And now for something completely different."
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