Messages in this thread Patch in this message | | | From | Andy Lutomirski <> | Subject | [PATCH] x86, vdso: Fix vdso2c's special_pages error checking | Date | Fri, 18 Jul 2014 10:21:59 -0700 |
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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.
Signed-off-by: Andy Lutomirski <luto@amacapital.net> --- arch/x86/vdso/vdso2c.h | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/arch/x86/vdso/vdso2c.h b/arch/x86/vdso/vdso2c.h index fd57829..0224987 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); } -- 1.9.3
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