Re: [PATCH 01/21] objtool: Fix seg fault in BT_FUNC() with fake jump

[Josh Poimboeuf]

On Thu, Jan 14, 2021 at 01:39:57PM -0600, Josh Poimboeuf wrote:
> Objtool appends a temporary fake jump at the end of alternative
> replacement instructions.  If the replacement code is empty -- resulting
> in patched nops -- the fake jump doesn't have a section.  When running
> objtool with '--backtrace', the fake jump's missing section can cause
> BT_FUNC() to trigger a seg fault when the NULL insn->sec is passed to
> offstr().
> 
> Fix it by ensuring fake jumps always have a section.
> 
> Fixes: 7697eee3ddd7 ("objtool: Add --backtrace support")
> Reported-by: Sami Tolvanen <samitolvanen@xxxxxxxxxx>
> Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>

This patch will probably end up getting dropped because fake jumps are
going away \o/

-- 
Josh