From 2feb6c83f5f22cb4b5060d8224f42d25dcb21fe7 Mon Sep 17 00:00:00 2001 From: Laszlo Ersek Date: Fri, 7 Nov 2014 17:17:48 +0100 Subject: [PATCH 01/41] dump: RHEL-specific fix for CPUState bug introduced by upstream c72bf4682 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Message-id: <1415380693-16593-2-git-send-email-lersek@redhat.com> Patchwork-id: 62187 O-Subject: [RHEL-7.1 qemu-kvm PATCH 01/26] dump: RHEL-specific fix for CPUState bug introduced by upstream c72bf4682 Bugzilla: 1161563 RH-Acked-by: Stefan Hajnoczi RH-Acked-by: Luiz Capitulino RH-Acked-by: dgibson In qemu-kvm-1.5.3-77.el7, the write_elf64_notes() and write_elf32_notes() functions are broken due to upstream commit c72bf4682. commit c72bf468259935a80ea185f2cbe807c3da9c1bbd Author: Jens Freimann Date: Fri Apr 19 16:45:06 2013 +0200 cpu: Move cpu_write_elfXX_note() functions to CPUState Convert cpu_write_elfXX_note() functions to CPUClass methods and pass CPUState as argument. Update target-i386 accordingly. Signed-off-by: Jens Freimann [AF: Retain stubs as CPUClass' default method implementation; style changes] Signed-off-by: Andreas Färber This commit changed the signature of the following functions so that they take CPUState rather than CPUArchState: - cpu_write_elf64_note() - cpu_write_elf64_qemunote() - cpu_write_elf32_note() - cpu_write_elf32_qemunote() The callers of these functions, write_elf64_notes() and write_elf32_notes(), each iterate over CPUArchState objects (starting from "first_cpu") *twice*, the first loop calling cpu_write_elfXX_note(), the second loop calling cpu_write_elfXX_qemunote(). The loop variable is called "env". When calling the above functions after c72bf468, "env" (of type CPUArchState) needs to be converted to CPUState, with the ENV_GET_CPU() macro. Now, even before c72bf468, the *first* loop in each of both callers used to do the conversion already, because cpu_write_elfXX_note() needs a CPU index, and that's only reachable via cpu_index(ENV_GET_CPU(env)). Therefore the first loop in each caller already set the "cpu" local variable correctly, for each "env" in question. However, the *second* loop in each caller had never done that, because cpu_write_elfXX_qemunote() had never needed a CPUState for anything. Upstream commit c72bf4682 simply replaced "env" with "cpu" in both loop bodies (in both callers). This was correct for the first loops (because they already had set "cpu" correctly), but the commit missed to add cpu = ENV_GET_CPU(env); to the second loops. Hence cpu_write_elfXX_qemunote() is always called with the last "cpu" value inherited from the first loop! (Which is why the bug is invisible for single-VCPU guests.) Add the missing assignments. For upstream, this was silently fixed in commit 182735efaf956ccab50b6d74a4fed163e0f35660 Author: Andreas Färber Date: Wed May 29 22:29:20 2013 +0200 cpu: Make first_cpu and next_cpu CPUState Move next_cpu from CPU_COMMON to CPUState. Move first_cpu variable to qom/cpu.h. gdbstub needs to use CPUState::env_ptr for now. cpu_copy() no longer needs to save and restore cpu_next. Acked-by: Paolo Bonzini [AF: Rebased, simplified cpu_copy()] Signed-off-by: Andreas Färber because it obviated and eliminated the cpu = ENV_GET_CPU(env); conversions completely. The bug-introducing commit c72bf4682 had been released in v1.5.0 (and it persisted even into 1.5.3, which is why we have it in RHEL). The silent / unintended fix (182735ef) is part of v1.6.0 (and we never backported that commit to RHEL-7.0). Signed-off-by: Laszlo Ersek Signed-off-by: Miroslav Rezanina --- dump.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/dump.c b/dump.c index b203a8d..a2b6e45 100644 --- a/dump.c +++ b/dump.c @@ -289,6 +289,7 @@ static int write_elf64_notes(DumpState *s) } for (env = first_cpu; env != NULL; env = env->next_cpu) { + cpu = ENV_GET_CPU(env); ret = cpu_write_elf64_qemunote(fd_write_vmcore, cpu, s); if (ret < 0) { dump_error(s, "dump: failed to write CPU status.\n"); @@ -341,6 +342,7 @@ static int write_elf32_notes(DumpState *s) } for (env = first_cpu; env != NULL; env = env->next_cpu) { + cpu = ENV_GET_CPU(env); ret = cpu_write_elf32_qemunote(fd_write_vmcore, cpu, s); if (ret < 0) { dump_error(s, "dump: failed to write CPU status.\n"); -- 1.8.3.1