Re: segfault with latest arm64 linux kernel build

On 17/06/2026 15:16, Ben Dooks wrote:
> On 17/06/2026 14:58, Ben Dooks wrote:
>> I'm getting a fault running the sparse check on current kernel.
>>
>>    CC [M]  drivers/gpu/drm/msm/msm_gem.o
>>    CHECK   /home/ben/linux/drivers/gpu/drm/msm/msm_gem.c
>> Segmentation fault
>>
>> The base of my tree is, however I have a pile of fixes
>> on this:
>>
>> commit 4b99990cdf9560e8a071640baf19f312e6ae02f4 (origin/master, 
>> origin/ HEAD)
>> Merge: 9c87e61e3c57 52d4ab1ca790
>> Author: Linus Torvalds <[email protected]>
>> Date:   Wed Jun 17 10:21:00 2026 +0100
>>
>>      Merge tag 'drm-next-2026-06-17' of https:// 
>> gitlab.freedesktop.org/ drm/kernel
> 
> I did get a coredump, and the error is at:
> 
>> 0  simplify_cgoto (insn=0x7f5fb0ab5240) at simplify.c:2737
>> 2737                    if (!target->ep)
>> (gdb) (gdb) backtrace
>> #0  simplify_cgoto (insn=0x7f5fb0ab5240) at simplify.c:2737
>> #1  simplify_instruction (insn=0x7f5fb0ab5240) at simplify.c:2850
>> #2  0x0000563adaef4e30 in clean_up_insns (ep=0x7f5fb0b48198) at 
>> optimize.c:42
>> #3  optimize (ep=ep@entry=0x7f5fb0b48198) at optimize.c:98
>> #4  0x0000563adaef49ae in linearize_fn (sym=0x2, base_type=<optimized 
>> out>) at linearize.c:2577
>> #5  linearize_symbol (sym=sym@entry=0x7f5fa9cc1b30) at linearize.c:2593
>> #6  0x0000563adaee7c2a in check_symbols (list=<optimized out>) at 
>> sparse.c:306
>> #7  0x0000563adaee779d in main (argc=<optimized out>, argv=<optimized 
>> out>) at sparse.c:332
> 
> 
> Not had time to go look into this further

my workaround/fix is:

diff --git a/simplify.c b/simplify.c
index 68c5f9c7..20f5cfc2 100644
--- a/simplify.c
+++ b/simplify.c
@@ -2734,6 +2734,8 @@ static int simplify_cgoto(struct instruction *insn)
                 break;
         case OP_LABEL:
                 target = def->bb_true;
+               if (!target)
+                       return 0;
                 if (!target->ep)
                         return 0;
                 FOR_EACH_PTR(insn->multijmp_list, jmp) {



-- 
Ben Dooks				http://www.codethink.co.uk/
Senior Engineer				Codethink - Providing Genius

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