[Crash-utility] Re: [PATCH v3] x86_64: Make ORC_REG_SP and ORC_REG_PREV_SP independent from kernel version

Hi Tao, On 8/6/26 8:16 AM, Tao Liu wrote: > Previously ORC_REG_SP and ORC_REG_PREV_SP will depend on kernel version > for their value, however this is fragile since distributions will > backport the upstream patch to a lower kernel version, thus break the > version assumption. > > This patch fixes by checking the value of ORC_REG_PREV_SP, which can be > get from orc_fp_entry. ORC_REG_PREV_SP's value can work as the indicator > of whether the current kernel have applied the upstream patch 1735858caa4b > ("objtool/x86: Reorder ORC register numbering"). > > Fixes: d0ee428664f9 ("x86_64: Fix "bt" command to use correct ORC register > values on Linux 7.1 and later") > > Signed-off-by: Tao Liu <ltao(a)redhat.com&gt; > --- > v3 -> v2: Remove data type query of orc_fp_entry, just use kernel_orc_entry_6_4 > which already contained in crash utility for bp_reg offset resolving. > --- > x86_64.c | 32 +++++++++++++++++++++++++------- > 1 file changed, 25 insertions(+), 7 deletions(-) > > diff --git a/x86_64.c b/x86_64.c > index 55648697baf3..d192f3bcdd20 100644 > --- a/x86_64.c > +++ b/x86_64.c > @@ -6661,6 +6661,9 @@ x86_64_ORC_init(void) > NULL > }; > struct ORC_data *orc; > + struct gnu_request request, *req; > + ulong value = 0; > + req = &request; > > MEMBER_OFFSET_INIT(inactive_task_frame_bp, "inactive_task_frame", "bp"); > MEMBER_OFFSET_INIT(inactive_task_frame_ret_addr, "inactive_task_frame", "ret_addr"); > @@ -6736,13 +6739,28 @@ x86_64_ORC_init(void) > if (orc->has_signal && !orc->has_end) > machdep->flags |= ORC_6_4; > > - /* See kernel commit 1735858caa4b */ > - if (THIS_KERNEL_VERSION >= LINUX(7,1,0)) { > - ORC_REG_SP = 3; > - ORC_REG_PREV_SP = 8; > - } else { > - ORC_REG_SP = 5; > - ORC_REG_PREV_SP = 1; > + /* Try get ORC_REG_(PREV)_SP */ > + ORC_REG_SP = 5; > + ORC_REG_PREV_SP = 1; How about use the newere values as default, and check the symbol data and set them as old ones if needed?