From: Peter Zijlstra peterz@infradead.org
mainline inclusion from mainline-v5.12-rc1 commit 87ccc826bf1c9e5ab4c2f649b404e02c63e47622 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I5LCHG CVE: NA
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Currently REG_SP_INDIRECT is unused but means (%rsp + offset), change it to mean (%rsp) + offset.
The reason is that we're going to swizzle stack in the middle of a C function with non-trivial stack footprint. This means that when the unwinder finds the ToS, it needs to dereference it (%rsp) and then add the offset to the next frame, resulting in: (%rsp) + offset
This is somewhat unfortunate, since REG_BP_INDIRECT is used (by DRAP) and thus needs to retain the current (%rbp + offset).
Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Reviewed-by: Miroslav Benes mbenes@suse.cz Acked-by: Josh Poimboeuf jpoimboe@redhat.com Signed-off-by: Yipeng Zou zouyipeng@huawei.com Reviewed-by: Zhang Jianhua chris.zjh@huawei.com Reviewed-by: Liao Chang liaochang1@huawei.com Signed-off-by: Yongqiang Liu liuyongqiang13@huawei.com --- arch/x86/kernel/unwind_orc.c | 5 ++++- tools/objtool/orc_dump.c | 2 +- 2 files changed, 5 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c index bafe953f5d7f..eea8ec5eca3b 100644 --- a/arch/x86/kernel/unwind_orc.c +++ b/arch/x86/kernel/unwind_orc.c @@ -450,7 +450,7 @@ bool unwind_next_frame(struct unwind_state *state) break;
case ORC_REG_SP_INDIRECT: - sp = state->sp + orc->sp_offset; + sp = state->sp; indirect = true; break;
@@ -500,6 +500,9 @@ bool unwind_next_frame(struct unwind_state *state) if (indirect) { if (!deref_stack_reg(state, sp, &sp)) goto err; + + if (orc->sp_reg == ORC_REG_SP_INDIRECT) + sp += orc->sp_offset; }
/* Find IP, SP and possibly regs: */ diff --git a/tools/objtool/orc_dump.c b/tools/objtool/orc_dump.c index faa444270ee3..ba28830aace2 100644 --- a/tools/objtool/orc_dump.c +++ b/tools/objtool/orc_dump.c @@ -64,7 +64,7 @@ static void print_reg(unsigned int reg, int offset) if (reg == ORC_REG_BP_INDIRECT) printf("(bp%+d)", offset); else if (reg == ORC_REG_SP_INDIRECT) - printf("(sp%+d)", offset); + printf("(sp)%+d", offset); else if (reg == ORC_REG_UNDEFINED) printf("(und)"); else