----- On Sep 18, 2018, at 9:53 AM, Mathieu Desnoyers mathieu.desnoyers@xxxxxxxxxxxx wrote: > On x86-64, the parametrized selftest code for rseq crashes with a > segmentation fault when compiled with -fpie. This happens when the > param_test binary is loaded at an address beyond 32-bit on x86-64. > > The issue is caused by use of a 32-bit register to hold the address > of the loop counter variable. > > Fix this by using a 64-bit register to calculate the address of the > loop counter variables as an offset from rip. Should this fix go through tip or the selftests tree ? Thanks, Mathieu > > Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx> > Cc: <stable@xxxxxxxxxxxxxxx> # v4.18 > Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> > Cc: Joel Fernandes <joelaf@xxxxxxxxxx> > Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> > Cc: Catalin Marinas <catalin.marinas@xxxxxxx> > Cc: Dave Watson <davejwatson@xxxxxx> > Cc: Will Deacon <will.deacon@xxxxxxx> > Cc: Shuah Khan <shuahkh@xxxxxxxxxxxxxxx> > Cc: Andi Kleen <andi@xxxxxxxxxxxxxx> > Cc: linux-kselftest@xxxxxxxxxxxxxxx > Cc: "H . Peter Anvin" <hpa@xxxxxxxxx> > Cc: Chris Lameter <cl@xxxxxxxxx> > Cc: Russell King <linux@xxxxxxxxxxxxxxxx> > Cc: Michael Kerrisk <mtk.manpages@xxxxxxxxx> > Cc: "Paul E . McKenney" <paulmck@xxxxxxxxxxxxxxxxxx> > Cc: Paul Turner <pjt@xxxxxxxxxx> > Cc: Boqun Feng <boqun.feng@xxxxxxxxx> > Cc: Josh Triplett <josh@xxxxxxxxxxxxxxxx> > Cc: Steven Rostedt <rostedt@xxxxxxxxxxx> > Cc: Ben Maurer <bmaurer@xxxxxx> > Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx> > Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> > --- > tools/testing/selftests/rseq/param_test.c | 19 ++++++++++--------- > 1 file changed, 10 insertions(+), 9 deletions(-) > > diff --git a/tools/testing/selftests/rseq/param_test.c > b/tools/testing/selftests/rseq/param_test.c > index 615252331813..4bc071525bf7 100644 > --- a/tools/testing/selftests/rseq/param_test.c > +++ b/tools/testing/selftests/rseq/param_test.c > @@ -56,15 +56,13 @@ unsigned int yield_mod_cnt, nr_abort; > printf(fmt, ## __VA_ARGS__); \ > } while (0) > > -#if defined(__x86_64__) || defined(__i386__) > +#ifdef __i386__ > > #define INJECT_ASM_REG "eax" > > #define RSEQ_INJECT_CLOBBER \ > , INJECT_ASM_REG > > -#ifdef __i386__ > - > #define RSEQ_INJECT_ASM(n) \ > "mov asm_loop_cnt_" #n ", %%" INJECT_ASM_REG "\n\t" \ > "test %%" INJECT_ASM_REG ",%%" INJECT_ASM_REG "\n\t" \ > @@ -76,9 +74,16 @@ unsigned int yield_mod_cnt, nr_abort; > > #elif defined(__x86_64__) > > +#define INJECT_ASM_REG_P "rax" > +#define INJECT_ASM_REG "eax" > + > +#define RSEQ_INJECT_CLOBBER \ > + , INJECT_ASM_REG_P \ > + , INJECT_ASM_REG > + > #define RSEQ_INJECT_ASM(n) \ > - "lea asm_loop_cnt_" #n "(%%rip), %%" INJECT_ASM_REG "\n\t" \ > - "mov (%%" INJECT_ASM_REG "), %%" INJECT_ASM_REG "\n\t" \ > + "lea asm_loop_cnt_" #n "(%%rip), %%" INJECT_ASM_REG_P "\n\t" \ > + "mov (%%" INJECT_ASM_REG_P "), %%" INJECT_ASM_REG "\n\t" \ > "test %%" INJECT_ASM_REG ",%%" INJECT_ASM_REG "\n\t" \ > "jz 333f\n\t" \ > "222:\n\t" \ > @@ -86,10 +91,6 @@ unsigned int yield_mod_cnt, nr_abort; > "jnz 222b\n\t" \ > "333:\n\t" > > -#else > -#error "Unsupported architecture" > -#endif > - > #elif defined(__ARMEL__) > > #define RSEQ_INJECT_INPUT \ > -- > 2.11.0 -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com
