diff options
| author | Andy Lutomirski <luto@amacapital.net> | 2014-07-31 01:59:49 +0400 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2014-09-24 11:55:38 +0400 |
| commit | f12c1f9002d27374fd205f6e692891116ca22272 (patch) | |
| tree | 72969fd94198bb5fa4429b7e36c870a7b820e67e /arch/x86/vdso | |
| parent | f3670394c29ff3730638762c1760fd2f624e6d7b (diff) | |
| download | linux-f12c1f9002d27374fd205f6e692891116ca22272.tar.xz | |
x86/vdso: Fix vdso2c's special_pages[] error checking
Stephen Rothwell's compiler did something amazing: it unrolled a
loop, discovered that one iteration of that loop contained an
always-true test, and emitted a warning that will IMO only serve
to convince people to disable the warning.
That bogus warning caused me to wonder what prompted such an
absurdity from his compiler, and I discovered that the code in
question was, in fact, completely wrong -- I was looking things
up in the wrong array.
This affects 3.16 as well, but the only effect is to screw up
the error checking a bit. vdso2c's output is unaffected.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/53d96ad5.80ywqrbs33ZBCQej%25akpm@linux-foundation.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/vdso')
| -rw-r--r-- | arch/x86/vdso/vdso2c.h | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/arch/x86/vdso/vdso2c.h b/arch/x86/vdso/vdso2c.h index fd57829b30d8..0224987556ce 100644 --- a/arch/x86/vdso/vdso2c.h +++ b/arch/x86/vdso/vdso2c.h @@ -109,16 +109,18 @@ static void BITSFUNC(go)(void *raw_addr, size_t raw_len, /* Validate mapping addresses. */ for (i = 0; i < sizeof(special_pages) / sizeof(special_pages[0]); i++) { - if (!syms[i]) + INT_BITS symval = syms[special_pages[i]]; + + if (!symval) continue; /* The mapping isn't used; ignore it. */ - if (syms[i] % 4096) + if (symval % 4096) fail("%s must be a multiple of 4096\n", required_syms[i].name); - if (syms[sym_vvar_start] > syms[i] + 4096) - fail("%s underruns begin_vvar\n", + if (symval + 4096 < syms[sym_vvar_start]) + fail("%s underruns vvar_start\n", required_syms[i].name); - if (syms[i] + 4096 > 0) + if (symval + 4096 > 0) fail("%s is on the wrong side of the vdso text\n", required_syms[i].name); } |