Hide Forgot
Description of problem: Valgrind reports an error on "str q0, [sp,#-16]!" which looks fine to me. Version-Release number of selected component (if applicable): valgrind-3.12.0-0.3.BETA1.fc26.aarch64 rust-1.12.0-5.fc26.aarch64 How reproducible: 100% Steps to Reproduce: 1. valgrind rustc -V Actual results: ==896== Invalid write of size 8 ==896== at 0x4AF3280: std::thread::Builder::name::h830c87465509c1aa (in /usr/lib64/libstd-40393716.so) ==896== by 0x4981D23: rustc_driver::run::ha6bc7b823ad700af (in /usr/lib64/librustc_driver-40393716.so) ==896== by 0x498F477: rustc_driver::main::h1cac4fa29a384d12 (in /usr/lib64/librustc_driver-40393716.so) ==896== by 0x4B3381B: __rust_maybe_catch_panic (in /usr/lib64/libstd-40393716.so) ==896== by 0x4B26373: std::rt::lang_start::h53bf99b0829cc03c (in /usr/lib64/libstd-40393716.so) ==896== by 0x4C0F46F: (below main) (in /usr/lib64/libc-2.24.90.so) ==896== Address 0xfff00e930 is on thread 1's stack ==896== 16 bytes below stack pointer Expected results: No errors. (hopefully!) Additional info: I used vgdb to get the disassembly at the mapped address - not sure if there's a more direct way. AIUI a "str q0, [sp,#-16]!" is basically a "push q0" because it's a pre-inc store, so it will update sp before writing the 128-bit q0. Valgrind's note about being "below stack pointer" is only true compared to the prior sp. That it calls this a "write of size 8", not 16 for q0, makes me think it's probably not decoding this instruction correctly. (gdb) p $sp $1 = (void *) 0xfff00e940 (gdb) disassemble /r Dump of assembler code for function _ZN3std6thread7Builder4name17h830c87465509c1aaE: 0x0000000004af3254 <+0>: f6 57 bd a9 stp x22, x21, [sp,#-48]! 0x0000000004af3258 <+4>: f4 4f 01 a9 stp x20, x19, [sp,#16] 0x0000000004af325c <+8>: fd 7b 02 a9 stp x29, x30, [sp,#32] 0x0000000004af3260 <+12>: fd 83 00 91 add x29, sp, #0x20 0x0000000004af3264 <+16>: e9 03 01 aa mov x9, x1 0x0000000004af3268 <+20>: ea 03 00 aa mov x10, x0 0x0000000004af326c <+24>: 40 05 40 a9 ldp x0, x1, [x10] 0x0000000004af3270 <+28>: 34 55 40 a9 ldp x20, x21, [x9] 0x0000000004af3274 <+32>: 36 09 40 f9 ldr x22, [x9,#16] 0x0000000004af3278 <+36>: 40 81 c1 3c ldur q0, [x10,#24] 0x0000000004af327c <+40>: f3 03 08 aa mov x19, x8 => 0x0000000004af3280 <+44>: e0 0f 9f 3c str q0, [sp,#-16]! 0x0000000004af3284 <+48>: 40 01 00 b4 cbz x0, 0x4af32ac <_ZN3std6thread7Builder4name17h830c87465509c1aaE+88> 0x0000000004af3288 <+52>: 21 01 00 b4 cbz x1, 0x4af32ac <_ZN3std6thread7Builder4name17h830c87465509c1aaE+88> 0x0000000004af328c <+56>: a8 a3 e3 d2 mov x8, #0x1d1d000000000000 // #2097833001424519168 0x0000000004af3290 <+60>: a8 a3 c3 f2 movk x8, #0x1d1d, lsl #32 0x0000000004af3294 <+64>: a8 a3 a3 f2 movk x8, #0x1d1d, lsl #16 0x0000000004af3298 <+68>: a8 a3 83 f2 movk x8, #0x1d1d 0x0000000004af329c <+72>: 3f 00 08 eb cmp x1, x8 0x0000000004af32a0 <+76>: 60 00 00 54 b.eq 0x4af32ac <_ZN3std6thread7Builder4name17h830c87465509c1aaE+88> 0x0000000004af32a4 <+80>: e2 03 00 32 orr w2, wzr, #0x1 0x0000000004af32a8 <+84>: 42 e7 ff 97 bl 0x4aecfb0 <__rust_deallocate@plt> 0x0000000004af32ac <+88>: e0 03 c0 3d ldr q0, [sp] 0x0000000004af32b0 <+92>: 74 56 00 a9 stp x20, x21, [x19] 0x0000000004af32b4 <+96>: 76 0a 00 f9 str x22, [x19,#16] 0x0000000004af32b8 <+100>: 60 82 81 3c stur q0, [x19,#24] 0x0000000004af32bc <+104>: bf 83 00 d1 sub sp, x29, #0x20 0x0000000004af32c0 <+108>: fd 7b 42 a9 ldp x29, x30, [sp,#32] 0x0000000004af32c4 <+112>: f4 4f 41 a9 ldp x20, x19, [sp,#16] 0x0000000004af32c8 <+116>: f6 57 c3 a8 ldp x22, x21, [sp],#48 0x0000000004af32cc <+120>: c0 03 5f d6 ret End of assembler dump. In a larger problem I was debugging earlier, one error report like this multiplied into many other "uninitialized value" errors related to that stack memory, which made so much noise that valgrind was unusable for the actual problem at hand.
This bug appears to have been reported against 'rawhide' during the Fedora 26 development cycle. Changing version to '26'.
This message is a reminder that Fedora 26 is nearing its end of life. Approximately 4 (four) weeks from now Fedora will stop maintaining and issuing updates for Fedora 26. It is Fedora's policy to close all bug reports from releases that are no longer maintained. At that time this bug will be closed as EOL if it remains open with a Fedora 'version' of '26'. Package Maintainer: If you wish for this bug to remain open because you plan to fix it in a currently maintained version, simply change the 'version' to a later Fedora version. Thank you for reporting this issue and we are sorry that we were not able to fix it before Fedora 26 is end of life. If you would still like to see this bug fixed and are able to reproduce it against a later version of Fedora, you are encouraged change the 'version' to a later Fedora version prior this bug is closed as described in the policy above. Although we aim to fix as many bugs as possible during every release's lifetime, sometimes those efforts are overtaken by events. Often a more recent Fedora release includes newer upstream software that fixes bugs or makes them obsolete.
AFAICS, current rust builds don't have that exact instruction anymore, and "valgrind rustc -V" doesn't complain. However, installing the old packages into rawhide, newer valgrind still has the same complaint. # rpm -q valgrind rust llvm-libs valgrind-3.13.0-18.fc29.aarch64 rust-1.12.0-5.fc26.aarch64 llvm-libs-3.8.0-1.fc25.aarch64 # valgrind rustc -V ==32== Memcheck, a memory error detector ==32== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al. ==32== Using Valgrind-3.13.0 and LibVEX; rerun with -h for copyright info ==32== Command: rustc -V ==32== ==32== Invalid write of size 8 ==32== at 0x4AA9280: std::thread::Builder::name (in /usr/lib64/libstd-40393716.so) ==32== by 0x4945D23: rustc_driver::run (in /usr/lib64/librustc_driver-40393716.so) ==32== by 0x4953477: rustc_driver::main (in /usr/lib64/librustc_driver-40393716.so) ==32== by 0x4AE981B: __rust_maybe_catch_panic (in /usr/lib64/libstd-40393716.so) ==32== by 0x4ADC373: std::rt::lang_start (in /usr/lib64/libstd-40393716.so) ==32== by 0x4BB7C1F: (below main) (in /usr/lib64/libc-2.26.90.so) ==32== Address 0x1ffefffb30 is on thread 1's stack ==32== 16 bytes below stack pointer Maybe we could write a target with manual asm to reproduce the error directly.
int main() { asm volatile ( "str q0, [sp,#-16]! \n" "ldr q0, [sp], #16 \n" ); return 0; } ==42== Invalid write of size 8 ==42== at 0x40055C: main (in /tmp/foo) ==42== Address 0x1fff000440 is on thread 1's stack ==42== 16 bytes below stack pointer
This bug appears to have been reported against 'rawhide' during the Fedora 29 development cycle. Changing version to '29'.
This message is a reminder that Fedora 29 is nearing its end of life. Fedora will stop maintaining and issuing updates for Fedora 29 on 2019-11-26. It is Fedora's policy to close all bug reports from releases that are no longer maintained. At that time this bug will be closed as EOL if it remains open with a Fedora 'version' of '29'. Package Maintainer: If you wish for this bug to remain open because you plan to fix it in a currently maintained version, simply change the 'version' to a later Fedora version. Thank you for reporting this issue and we are sorry that we were not able to fix it before Fedora 29 is end of life. If you would still like to see this bug fixed and are able to reproduce it against a later version of Fedora, you are encouraged change the 'version' to a later Fedora version prior this bug is closed as described in the policy above. Although we aim to fix as many bugs as possible during every release's lifetime, sometimes those efforts are overtaken by events. Often a more recent Fedora release includes newer upstream software that fixes bugs or makes them obsolete.
Fedora 29 changed to end-of-life (EOL) status on 2019-11-26. Fedora 29 is no longer maintained, which means that it will not receive any further security or bug fix updates. As a result we are closing this bug. If you can reproduce this bug against a currently maintained version of Fedora please feel free to reopen this bug against that version. If you are unable to reopen this bug, please file a new report against the current release. If you experience problems, please add a comment to this bug. Thank you for reporting this bug and we are sorry it could not be fixed.