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Diffstat (limited to 'gitlab/issues/target_i386/host_x86/accel_missing/1910.toml')
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1 files changed, 0 insertions, 70 deletions
diff --git a/gitlab/issues/target_i386/host_x86/accel_missing/1910.toml b/gitlab/issues/target_i386/host_x86/accel_missing/1910.toml deleted file mode 100644 index 783fd1a6d..000000000 --- a/gitlab/issues/target_i386/host_x86/accel_missing/1910.toml +++ /dev/null @@ -1,70 +0,0 @@ -id = 1910 -title = "Signal handlers in x86_64 userspace have wrongly aligned stack" -state = "closed" -created_at = "2023-09-28T08:17:08.602Z" -closed_at = "2023-09-29T14:53:31.357Z" -labels = ["Closed::Duplicate", "host: x86", "linux-user", "target: i386"] -url = "https://gitlab.com/qemu-project/qemu/-/issues/1910" -host-os = "openSUSE Tumbleweed" -host-arch = "x86_64" -qemu-version = "8.1.0" -guest-os = "Linux" -guest-arch = "x86_64" -description = """Various applications crash in signal handlers due to `movaps` getting a misaligned stack address. For some reason this is reported as a NULL deref, but `gdb` clearly shows the true cause. - -```plaintext -> qemu-x86_64 /usr/bin/ruby -e '`true`' --e:1: [BUG] Segmentation fault at 0x0000000000000000 -ruby 3.2.2 (2023-03-30 revision e51014f9c0) [x86_64-linux-gnu] - --- Control frame information ----------------------------------------------- -c:0003 p:---- s:0011 e:000010 CFUNC :` -c:0002 p:0005 s:0006 e:000005 EVAL -e:1 [FINISH] -c:0001 p:0000 s:0003 E:0015b0 DUMMY [FINISH] - --- Ruby level backtrace information ---------------------------------------- --e:1:in `<main>' --e:1:in ``' - --- Machine register context ------------------------------------------------ - RIP: 0x00002aaaab50f98a RBP: 0x00002aaaabb136b8 RSP: 0x00002aaaab2a9c98 - RAX: 0x0000000000000000 RBX: 0x0000000000004946 RCX: 0x0000000000000000 - RDX: 0x00002aaaab2a9c98 RDI: 0x000000000caf0000 RSI: 0x0000000000000000 - R8: 0x00002aaaab2aaa50 R9: 0x0000000000000050 R10: 0x0000000000000008 - R11: 0x0000000000000000 R12: 0x0000000000000002 R13: 0x0000000000007310 - R14: 0x0000000000005e10 R15: 0x00002aaab0537f20 EFL: 0x0000000000000246 - --- C level backtrace information ------------------------------------------- -``` - -```plaintext -(gdb) x/i $pc -=> 0x2aaaab50f98a: movaps %xmm0,(%rsp) -(gdb) p/x $rsp -$3 = 0x2aaaab2a9998 -```""" -reproduce = """1. ```qemu-x86_64 /usr/bin/ruby -e '`true`'```""" -additional = """The x86_64 psABI says: - -> the value (%rsp − 8) is always a multiple of 16 when control is transferred to the function entry point. - -However, when QEMU jumps to the signal handler, $rsp is aligned to 16B, i.e. ends in `0x..0`. - -The relevant kernel code: - -https://elixir.bootlin.com/linux/v6.5.5/source/arch/x86/kernel/signal.c#L123 - -```plaintext -\tsp -= frame_size; - -\tif (ia32_frame) -\t\t/* -\t\t * Align the stack pointer according to the i386 ABI, -\t\t * i.e. so that on function entry ((sp + 4) & 15) == 0. -\t\t */ -\t\tsp = ((sp + 4) & -FRAME_ALIGNMENT) - 4; -\telse -\t\tsp = round_down(sp, FRAME_ALIGNMENT) - 8; -``` - -CC @lvivier @bonzini @rth7680""" |