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powerpc/ftrace: Fix inverted check of create_branch()

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In commit 24a1bdc35, "Fix ABIv2 issues with __ftrace_make_call", Anton
changed the logic that creates and patches the branch, and added a
thinko in the check of create_branch(). create_branch() returns the
instruction that was generated, so if we get zero then it succeeded.

The result is we can't ftrace modules:

  Branch out of range
  WARNING: at ../kernel/trace/ftrace.c:1638
  ftrace failed to modify [<d000000004ba001c>] fuse_req_init_context+0x1c/0x90 [fuse]

We should probably fix patch_instruction() to do that check and make the
API saner, but that's a separate patch. For now just invert the test.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Michael Ellerman 2014-06-17 16:15:34 +10:00 committed by Benjamin Herrenschmidt
parent dfc382a19a
commit b7b348c682
1 changed files with 1 additions and 1 deletions
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2
arch/powerpc/kernel/ftrace.c
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@ -320,7 +320,7 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
} }
/* Ensure branch is within 24 bits */ /* Ensure branch is within 24 bits */
if (create_branch(ip, rec->arch.mod->arch.tramp, BRANCH_SET_LINK)) { if (!create_branch(ip, rec->arch.mod->arch.tramp, BRANCH_SET_LINK)) {
printk(KERN_ERR "Branch out of range"); printk(KERN_ERR "Branch out of range");
return -EINVAL; return -EINVAL;
} }