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objtool: Fix pv_ops noinstr validation

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Boris reported that in one of his randconfig builds, objtool got
infinitely stuck. Turns out there's trivial list corruption in the
pv_ops tracking when a function is both in a static table and in a code
assignment.

Avoid re-adding function to the pv_ops[] lists when they're already on
it.

Fixes: db2b0c5d7b6f ("objtool: Support pv_opsindirect calls for noinstr")
Reported-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Tested-by: Borislav Petkov <bp@alien8.de>
Link: https://lkml.kernel.org/r/20211202204534.GA16608@worktop.programming.kicks-ass.net
This commit is contained in:
Peter Zijlstra 2021-12-02 21:45:34 +01:00 committed by Borislav Petkov
parent b50db7095f
commit 988f01683c
2 changed files with 5 additions and 0 deletions
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1
tools/objtool/elf.c
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@ -375,6 +375,7 @@ static int read_symbols(struct elf *elf)
return -1;
}
memset(sym, 0, sizeof(*sym));
INIT_LIST_HEAD(&sym->pv_target);
sym->alias = sym;
sym->idx = i;

4
tools/objtool/objtool.c
View File

@ -153,6 +153,10 @@ void objtool_pv_add(struct objtool_file *f, int idx, struct symbol *func)
!strcmp(func->name, "_paravirt_ident_64"))
return;
/* already added this function */
if (!list_empty(&func->pv_target))
return;
list_add(&func->pv_target, &f->pv_ops[idx].targets);
f->pv_ops[idx].clean = false;
}