Re: [Bug 1910505] [NEW] atomic failure linking with --enable-sanitizers on 32-bit Linux hosts

[Philippe Mathieu-Daudé]

Cc'ing atomic team and qemu-block@ for "qemu/stats64.h".

On 1/7/21 9:40 AM, Philippe Mathieu-Daudé wrote:
> Public bug reported:
> 
> As of commit 50536341b47, using --enable-sanitizers on 32-bit Linux host:
> - displays various warnings
> - fails linking
> 
> Using Ubuntu 18.04 (release 20201211.1) and Clang10 on i386:
> 
> [139/675] Compiling C object softmmu.fa.p/softmmu_icount.c.o
> In file included from ../softmmu/icount.c:31:
> In file included from include/exec/exec-all.h:23:
> In file included from ../target/mips/cpu.h:4:
> In file included from ../target/mips/cpu-qom.h:23:
> In file included from include/hw/core/cpu.h:23:
> In file included from include/hw/qdev-core.h:5:
> In file included from include/qemu/bitmap.h:16:
> In file included from include/qemu/bitops.h:17:
> include/qemu/atomic.h:463:12: warning: misaligned atomic operation may
> incur significant performance penalty [-Watomic-alignment]
>     return qatomic_read__nocheck(ptr);
>            ^
> include/qemu/atomic.h:129:5: note: expanded from macro
> 'qatomic_read__nocheck'
>     __atomic_load_n(ptr, __ATOMIC_RELAXED)
>     ^
> include/qemu/atomic.h:473:5: warning: misaligned atomic operation may
> incur significant performance penalty [-Watomic-alignment]
>     qatomic_set__nocheck(ptr, val);
>     ^
> include/qemu/atomic.h:138:5: note: expanded from macro
> 'qatomic_set__nocheck'
>     __atomic_store_n(ptr, i, __ATOMIC_RELAXED)
>     ^
> 2 warnings generated.
> [...]
> 
> [850/2216] Linking target tests/test-hbitmap
> FAILED: tests/test-hbitmap
> clang  -o tests/test-hbitmap tests/test-hbitmap.p/test-hbitmap.c.o
> tests/test-hbitmap.p/iothread.c.o -Wl,--as-needed -Wl,--no-undefined
> -pie -Wl,--whole-archive libblock.fa libcrypto.fa libauthz.fa libqom.fa
> libio.fa -Wl,--no-whole-archive -Wl,--warn-common -fsanitize=undefined
> -fsanitize=address -Wl,-z,relro -Wl,-z,now -m32 -ggdb
> -fstack-protector-strong -Wl,--start-group libqemuutil.a
> subprojects/libvhost-user/libvhost-user-glib.a
> subprojects/libvhost-user/libvhost-user.a libblock.fa libcrypto.fa
> libauthz.fa libqom.fa libio.fa @block.syms -lgio-2.0 -lgobject-2.0
> -lglib-2.0 -lgio-2.0 -lgobject-2.0 -lglib-2.0 -pthread -lutil -lgnutls
> -lm -lgthread-2.0 -lglib-2.0 /usr/lib/i386-linux-gnu/libglib-2.0.so
> -liscsi -lgthread-2.0 -lglib-2.0 -laio -lcurl
> /usr/lib/i386-linux-gnu/libz.so -lrbd -lrados -lnettle -lgnutls
> -Wl,--end-group
> libblock.fa(block_io.c.o): In function `stat64_max':
> include/qemu/stats64.h:58: undefined reference to `__atomic_load_8'
> include/qemu/stats64.h:60: undefined reference to
> `__atomic_compare_exchange_8'
> libblock.fa(block_qapi.c.o): In function `stat64_get':
> include/qemu/stats64.h:40: undefined reference to `__atomic_load_8'
> libqemuutil.a(util_qsp.c.o): In function `qatomic_set_u64':
> include/qemu/atomic.h:478: undefined reference to `__atomic_store_8'
> libqemuutil.a(util_qsp.c.o): In function `qatomic_read_u64':
> include/qemu/atomic.h:468: undefined reference to `__atomic_load_8'
> clang: error: linker command failed with exit code 1 (use -v to see
> invocation)
> 
> Issue previously reported on the list here:
> https://www.mail-archive.com/qemu-devel@nongnu.org/msg770128.html
> 
> ** Affects: qemu
>      Importance: Undecided
>          Status: New
>