The patch below does not apply to the 4.0-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.
thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From b035b60ded132592055c0f9bd1cc280259c7de4b Mon Sep 17 00:00:00 2001 From: Michael Holzheu <[email protected]> Date: Thu, 21 May 2015 15:39:31 +0200 Subject: [PATCH] s390/bpf: Fix backward jumps Currently all backward jumps crash for JITed s390x eBPF programs with an illegal instruction program check and kernel panic. Because for negative values the opcode of the jump instruction is overriden by the negative branch offset an illegal instruction is generated by the JIT: 000003ff802da378: c01100000002 lgfi %r1,2 000003ff802da37e: fffffff52065 unknown <-- illegal instruction 000003ff802da384: b904002e lgr %r2,%r14 So fix this and mask the offset in order not to damage the opcode. Cc: [email protected] # 4.0+ Signed-off-by: Michael Holzheu <[email protected]> Signed-off-by: Martin Schwidefsky <[email protected]> diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c index d3766dd67e23..fee782acc2ee 100644 --- a/arch/s390/net/bpf_jit_comp.c +++ b/arch/s390/net/bpf_jit_comp.c @@ -250,7 +250,7 @@ static inline void reg_set_seen(struct bpf_jit *jit, u32 b1) ({ \ /* Branch instruction needs 6 bytes */ \ int rel = (addrs[i + off + 1] - (addrs[i + 1] - 6)) / 2;\ - _EMIT6(op1 | reg(b1, b2) << 16 | rel, op2 | mask); \ + _EMIT6(op1 | reg(b1, b2) << 16 | (rel & 0xffff), op2 | mask); \ REG_SET_SEEN(b1); \ REG_SET_SEEN(b2); \ }) -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
