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authorHari Bathini <hbathini@linux.ibm.com>2021-10-25 11:26:49 +0530
committerMichael Ellerman <mpe@ellerman.id.au>2021-10-28 00:08:32 +1100
commit44a8214de96bafb5210e43bfa2c97c19bf75af3d (patch)
treecdfb0d8098d65f703b1ebfbbe06e7c4c446d1604 /arch/powerpc
parentcb662608e546d755e3e1b51b30a269459323bf24 (diff)
powerpc/bpf: Fix write protecting JIT code
Running program with bpf-to-bpf function calls results in data access exception (0x300) with the below call trace: bpf_int_jit_compile+0x238/0x750 (unreliable) bpf_check+0x2008/0x2710 bpf_prog_load+0xb00/0x13a0 __sys_bpf+0x6f4/0x27c0 sys_bpf+0x2c/0x40 system_call_exception+0x164/0x330 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. Fixes: 62e3d4210ac9 ("powerpc/bpf: Write protect JIT code") Cc: stable@vger.kernel.org # v5.14+ Signed-off-by: Hari Bathini <hbathini@linux.ibm.com> Reviewed-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20211025055649.114728-1-hbathini@linux.ibm.com
Diffstat (limited to 'arch/powerpc')
-rw-r--r--arch/powerpc/net/bpf_jit_comp.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c
index 53aefee3fe70..0df97af4dcaf 100644
--- a/arch/powerpc/net/bpf_jit_comp.c
+++ b/arch/powerpc/net/bpf_jit_comp.c
@@ -237,8 +237,8 @@ skip_codegen_passes:
fp->jited_len = alloclen;
bpf_flush_icache(bpf_hdr, (u8 *)bpf_hdr + (bpf_hdr->pages * PAGE_SIZE));
- bpf_jit_binary_lock_ro(bpf_hdr);
if (!fp->is_func || extra_pass) {
+ bpf_jit_binary_lock_ro(bpf_hdr);
bpf_prog_fill_jited_linfo(fp, addrs);
out_addrs:
kfree(addrs);