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| author | Haoran Jiang <jianghaoran@kylinos.cn> | 2025-08-05 14:00:22 +0300 |
|---|---|---|
| committer | Huacai Chen <chenhuacai@loongson.cn> | 2025-08-05 14:00:22 +0300 |
| commit | cd39d9e6b7e4c58fa77783e7aedf7ada51d02ea3 (patch) | |
| tree | 2071534f4bc1a5fb63b985632586508b7b4eb56c /scripts/gdb/linux/dmesg.py | |
| parent | 6abf17d690d83d25f6d00a1a2cd3553c7d20c2d8 (diff) | |
| download | linux-cd39d9e6b7e4c58fa77783e7aedf7ada51d02ea3.tar.xz | |
LoongArch: BPF: Fix jump offset calculation in tailcall
The extra pass of bpf_int_jit_compile() skips JIT context initialization
which essentially skips offset calculation leaving out_offset = -1, so
the jmp_offset in emit_bpf_tail_call is calculated by
"#define jmp_offset (out_offset - (cur_offset))"
is a negative number, which is wrong. The final generated assembly are
as follow.
54: bgeu $a2, $t1, -8 # 0x0000004c
58: addi.d $a6, $s5, -1
5c: bltz $a6, -16 # 0x0000004c
60: alsl.d $t2, $a2, $a1, 0x3
64: ld.d $t2, $t2, 264
68: beq $t2, $zero, -28 # 0x0000004c
Before apply this patch, the follow test case will reveal soft lock issues.
cd tools/testing/selftests/bpf/
./test_progs --allow=tailcalls/tailcall_bpf2bpf_1
dmesg:
watchdog: BUG: soft lockup - CPU#2 stuck for 26s! [test_progs:25056]
Cc: stable@vger.kernel.org
Fixes: 5dc615520c4d ("LoongArch: Add BPF JIT support")
Reviewed-by: Hengqi Chen <hengqi.chen@gmail.com>
Signed-off-by: Haoran Jiang <jianghaoran@kylinos.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Diffstat (limited to 'scripts/gdb/linux/dmesg.py')
0 files changed, 0 insertions, 0 deletions