26bac7170d
Update to 2.5.0 OBS-URL: https://build.opensuse.org/request/show/354829 OBS-URL: https://build.opensuse.org/package/show/Virtualization/qemu?expand=0&rev=284
43 lines
1.6 KiB
Diff
43 lines
1.6 KiB
Diff
From cce489197692907986c6fec5c089daf57d46b58b Mon Sep 17 00:00:00 2001
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From: Alexander Graf <agraf@suse.de>
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Date: Fri, 13 Jan 2012 17:05:41 +0100
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Subject: [PATCH] linux-user: fix segfault deadlock
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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When entering the guest we take a lock to ensure that nobody else messes
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with our TB chaining while we're doing it. If we get a segfault inside that
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code, we manage to work on, but will not unlock the lock.
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This patch forces unlocking of that lock in the segv handler. I'm not sure
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this is the right approach though. Maybe we should rather make sure we don't
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segfault in the code? I would greatly appreciate someone more intelligible
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than me to look at this :).
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Example code to trigger this is at: http://csgraf.de/tmp/conftest.c
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Reported-by: Fabio Erculiani <lxnay@sabayon.org>
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Signed-off-by: Alexander Graf <agraf@suse.de>
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[AF: Drop spinlock_safe_unlock() and switch to tb_lock_reset() (bonzini)]
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Signed-off-by: Andreas Färber <afaerber@suse.de>
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---
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user-exec.c | 4 ++++
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1 file changed, 4 insertions(+)
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diff --git a/user-exec.c b/user-exec.c
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index 8ad89a4..02c5c3b 100644
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--- a/user-exec.c
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+++ b/user-exec.c
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@@ -95,6 +95,10 @@ static inline int handle_cpu_signal(uintptr_t pc, unsigned long address,
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printf("qemu: SIGSEGV pc=0x%08lx address=%08lx w=%d oldset=0x%08lx\n",
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pc, address, is_write, *(unsigned long *)old_set);
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#endif
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+
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+ /* Maybe we're still holding the TB fiddling lock? */
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+ tb_lock_reset();
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+
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/* XXX: locking issue */
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if (is_write && h2g_valid(address)
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&& page_unprotect(h2g(address), pc, puc)) {
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