Thread (11 messages) 11 messages, 4 authors, 2026-03-25

Re: [PATCH bpf-next v10 4/5] bpf, x86: Emit ENDBR for indirect jump targets

From: Leon Hwang <hidden>
Date: 2026-03-25 10:13:34
Also in: bpf, lkml

On Tue, Mar 24, 2026 at 08:20:51PM +0800, Xu Kuohai wrote:
From: Xu Kuohai <redacted>

On CPUs that support CET/IBT, the indirect jump selftest triggers
a kernel panic because the indirect jump targets lack ENDBR
instructions.

To fix it, emit an ENDBR instruction to each indirect jump target. Since
the ENDBR instruction shifts the position of original jited instructions,
fix the instruction address calculation wherever the addresses are used.

For reference, below is a sample panic log.

Missing ENDBR: bpf_prog_2e5f1c71c13ac3e0_big_jump_table+0x97/0xe1
------------[ cut here ]------------
kernel BUG at arch/x86/kernel/cet.c:133!
Oops: invalid opcode: 0000 [#1] SMP NOPTI

...

 ? 0xffffffffc00fb258
 ? bpf_prog_2e5f1c71c13ac3e0_big_jump_table+0x97/0xe1
 bpf_prog_test_run_syscall+0x110/0x2f0
 ? fdget+0xba/0xe0
 __sys_bpf+0xe4b/0x2590
 ? __kmalloc_node_track_caller_noprof+0x1c7/0x680
 ? bpf_prog_test_run_syscall+0x215/0x2f0
 __x64_sys_bpf+0x21/0x30
 do_syscall_64+0x85/0x620
 ? bpf_prog_test_run_syscall+0x1e2/0x2f0

Fixes: 493d9e0d6083 ("bpf, x86: add support for indirect jumps")
Reviewed-by: Anton Protopopov <redacted>
Signed-off-by: Xu Kuohai <redacted>
Acked-by: Leon Hwang <redacted>

[...]
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