On 2/11/25 1:54 PM, Andrew Cooper wrote:
While fixing some common/arch boundaries for UBSAN support on other
architectures, the following debugging patch:
diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index c1f2d1b89d43..58d1d048d339 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -504,6 +504,8 @@ void asmlinkage __init start_xen(unsigned long fdt_paddr)
system_state = SYS_STATE_active;
+ dump_execution_state();
+
for_each_domain( d )
domain_unpause_by_systemcontroller(d);
failed with:
(XEN) *** Serial input to DOM0 (type 'CTRL-a' three times to switch input)
(XEN) CPU0: Unexpected Trap: Undefined Instruction
(XEN) ----[ Xen-4.20-rc arm32 debug=n Not tainted ]----
(XEN) CPU: 0
<snip>
(XEN)
(XEN) ****************************************
(XEN) Panic on CPU 0:
(XEN) CPU0: Unexpected Trap: Undefined Instruction
(XEN) ****************************************
This is because the condition for init text is wrong. While there's nothing
interesting from that point onwards in start_xen(), it's also wrong for
livepatches too.
Use is_active_kernel_text() which is the correct test for this purpose, and is
aware of init and livepatch regions as well as their lifetimes.
Fixes: 3e802c6ca1fb ("xen/arm: Correctly support WARN_ON")
Signed-off-by: Andrew Cooper<andrew.coop...@citrix.com>
Release-Acked-by:Oleksii Kurochko <oleksii.kuroc...@gmail.com> ~ Oleksii
---
CC: Stefano Stabellini<sstabell...@kernel.org>
CC: Julien Grall<jul...@xen.org>
CC: Volodymyr Babchuk<volodymyr_babc...@epam.com>
CC: Bertrand Marquis<bertrand.marq...@arm.com>
CC: Michal Orzel<michal.or...@amd.com>
CC: Oleksii Kurochko<oleksii.kuroc...@gmail.com>
v2:
* Split out change to dump_execution_state()
Sample run going wrong:
https://gitlab.com/xen-project/people/andyhhp/xen/-/jobs/9078570105
Sample run with dump_execution_state() working:
https://gitlab.com/xen-project/people/andyhhp/xen/-/jobs/9079185111
---
xen/arch/arm/arm32/traps.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/xen/arch/arm/arm32/traps.c b/xen/arch/arm/arm32/traps.c
index a2fc1c22cbc9..b88d41811b49 100644
--- a/xen/arch/arm/arm32/traps.c
+++ b/xen/arch/arm/arm32/traps.c
@@ -36,8 +36,7 @@ void do_trap_undefined_instruction(struct cpu_user_regs *regs)
uint32_t pc = regs->pc;
uint32_t instr;
- if ( !is_kernel_text(pc) &&
- (system_state >= SYS_STATE_active || !is_kernel_inittext(pc)) )
+ if ( !is_active_kernel_text(pc) )
goto die;
/* PC should be always a multiple of 4, as Xen is using ARM instruction set */
