Commit-ID: f12c1f9002d27374fd205f6e692891116ca22272 Gitweb: http://git.kernel.org/tip/f12c1f9002d27374fd205f6e692891116ca22272 Author: Andy Lutomirski <[email protected]> AuthorDate: Wed, 30 Jul 2014 14:59:49 -0700 Committer: Ingo Molnar <[email protected]> CommitDate: Wed, 24 Sep 2014 09:55:38 +0200
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 <[email protected]> Signed-off-by: Andy Lutomirski <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Linus Torvalds <[email protected]> Link: http://lkml.kernel.org/r/53d96ad5.80ywqrbs33zbcqej%[email protected] Signed-off-by: Ingo Molnar <[email protected]> --- 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); } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
