On 10/25/21 8:15 AM, Naveen N. Rao wrote:
Hari Bathini wrote:Running program with bpf-to-bpf function calls results in data access exception (0x300) with the below call trace: [c000000000113f28] bpf_int_jit_compile+0x238/0x750 (unreliable) [c00000000037d2f8] bpf_check+0x2008/0x2710 [c000000000360050] bpf_prog_load+0xb00/0x13a0 [c000000000361d94] __sys_bpf+0x6f4/0x27c0 [c000000000363f0c] sys_bpf+0x2c/0x40 [c000000000032434] system_call_exception+0x164/0x330 [c00000000000c1e8] system_call_vectored_common+0xe8/0x278 as bpf_int_jit_compile() tries writing to write protected JIT code location during the extra pass. Fix it by holding off write protection of JIT code until the extra pass, where branch target addresses fixup happens. Cc: stable@xxxxxxxxxxxxxxx Fixes: 62e3d4210ac9 ("powerpc/bpf: Write protect JIT code") Signed-off-by: Hari Bathini <hbathini@xxxxxxxxxxxxx> --- arch/powerpc/net/bpf_jit_comp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)Thanks for the fix! Reviewed-by: Naveen N. Rao <naveen.n.rao@xxxxxxxxxxxxxxxxxx>
LGTM, I presume this fix will be routed via Michael. BPF selftests have plenty of BPF-to-BPF calls in there, too bad this was caught so late. :/
