Re: [PATCH] hppa: avoid NULL dereference of sym_map in elf_machine_rela()

[John David Anglin <dave dot anglin at bell dot net>]

On 31-Oct-14, at 6:38 PM, Aaro Koskinen wrote:

> > Rather, the right solution is probably to find (or add) some switch  
> > to GCC
> > that changes what it emits from being a call to abort to be something
> > different.  It's possible that abort is OK and we just need to  
> > define an
> > appropriately minimal abort in rtld.  But it needs to be looked into.
>
> The other quick workaround I could find is -fno-delete-null-pointer- 
> checks.
>
> "[...] other optimization passes in GCC use this flag to control  
> global
> dataflow analyses that eliminate useless checks for null pointers  
> [...]"

This suggests that GCC deletes a null check that is useful.

The attached patch implements a trap insn and __builtin_trap().  It  
generates
a conditional trap (SIGFPE).  Carlos has used another instruction that  
generates
an illegal instruction trap.

Dave
--
John David Anglin	dave.anglin@bell.net

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