From 9a7555e54da2dd55f7b6580cf7497b2d5291f7ab Mon Sep 17 00:00:00 2001 From: Simon Hausmann Date: Fri, 24 Aug 2018 10:40:26 +0200 Subject: Fix failing assertions in QML when running under qemu Unfortunately the user-space emulation mode of qemu does not implement MADV_DONTNEED, which is a feature that the garbage collector of QML relies on. Patch is submitted to the qemu list and included here to fix the imminent issue we're seeing. Task-number: QTBUG-68349 Change-Id: I2bb15513a1e5a7ad03eeae98d77691336985a20f Reviewed-by: Sami Nurmenniemi Reviewed-by: Lars Knoll --- .../qtci-linux-Ubuntu-16.04-x86_64/03-qemu.sh | 72 ++++++++++++++++++++++ 1 file changed, 72 insertions(+) (limited to 'coin/provisioning/qtci-linux-Ubuntu-16.04-x86_64') diff --git a/coin/provisioning/qtci-linux-Ubuntu-16.04-x86_64/03-qemu.sh b/coin/provisioning/qtci-linux-Ubuntu-16.04-x86_64/03-qemu.sh index b2057b21..edabeb0c 100755 --- a/coin/provisioning/qtci-linux-Ubuntu-16.04-x86_64/03-qemu.sh +++ b/coin/provisioning/qtci-linux-Ubuntu-16.04-x86_64/03-qemu.sh @@ -46,6 +46,78 @@ cd "$tempDir" #latest commit from the master proven to work git checkout c7f1cf01b8245762ca5864e835d84f6677ae8b1f git submodule update --init pixman + +patch -p1 < +Date: Fri, 24 Aug 2018 10:38:29 +0200 +Subject: [PATCH] linux-user: add support for MADV_DONTNEED + +Most flags to madvise() are just hints, so typically ignoring the +syscall and returning okay is fine. However applications exist that do +rely on MADV_DONTNEED behavior to guarantee that upon subsequent access +the mapping is refreshed from the backing file or zero for anonymous +mappings. +--- + linux-user/mmap.c | 18 ++++++++++++++++++ + linux-user/qemu.h | 1 + + linux-user/syscall.c | 6 +----- + 3 files changed, 20 insertions(+), 5 deletions(-) + +diff --git a/linux-user/mmap.c b/linux-user/mmap.c +index 61685bf79e..cb3069f27e 100644 +--- a/linux-user/mmap.c ++++ b/linux-user/mmap.c +@@ -764,3 +764,16 @@ int target_msync(abi_ulong start, abi_ulong len, int flags) + start &= qemu_host_page_mask; + return msync(g2h(start), end - start, flags); + } ++ ++int target_madvise(abi_ulong start, abi_ulong len, int flags) ++{ ++ /* A straight passthrough may not be safe because qemu sometimes ++ turns private file-backed mappings into anonymous mappings. ++ Most flags are hints, except for MADV_DONTNEED that applications ++ may rely on to zero out pages, so we pass that through. ++ Otherwise returning success is ok. */ ++ if (flags & MADV_DONTNEED) { ++ return madvise(g2h(start), len, MADV_DONTNEED); ++ } ++ return 0; ++} +diff --git a/linux-user/qemu.h b/linux-user/qemu.h +index 4edd7d0c08..3c975909a1 100644 +--- a/linux-user/qemu.h ++++ b/linux-user/qemu.h +@@ -429,6 +429,7 @@ int target_munmap(abi_ulong start, abi_ulong len); + abi_long target_mremap(abi_ulong old_addr, abi_ulong old_size, + abi_ulong new_size, unsigned long flags, + abi_ulong new_addr); ++int target_madvise(abi_ulong start, abi_ulong len, int flags); + int target_msync(abi_ulong start, abi_ulong len, int flags); + extern unsigned long last_brk; + extern abi_ulong mmap_next_start; +diff --git a/linux-user/syscall.c b/linux-user/syscall.c +index 11a311f9db..94d8abc745 100644 +--- a/linux-user/syscall.c ++++ b/linux-user/syscall.c +@@ -11148,11 +11148,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, + + #ifdef TARGET_NR_madvise + case TARGET_NR_madvise: +- /* A straight passthrough may not be safe because qemu sometimes +- turns private file-backed mappings into anonymous mappings. +- This will break MADV_DONTNEED. +- This is a hint, so ignoring and returning success is ok. */ +- ret = get_errno(0); ++ ret = get_errno(target_madvise(arg1, arg2, arg3)); + break; + #endif + #if TARGET_ABI_BITS == 32 +-- +2.17.1 +EOT + ./configure --target-list=arm-linux-user,aarch64-linux-user --static make sudo make install -- cgit v1.2.3