115 lines
3.4 KiB
Diff
115 lines
3.4 KiB
Diff
From 03f9360715731f18e4fdae7b30aa34b30dddcd57 Mon Sep 17 00:00:00 2001
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From: HATAYAMA Daisuke <d.hatayama@fujitsu.com>
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Date: Sat, 26 Mar 2022 21:42:02 +0900
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Subject: [PATCH 4/8] x86: Fix failure of collecting vsyscall mapping due to
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change of enum type of vsyscall_mode
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vsyscall mapping fails to get collected because the commit
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bd49e16e3339 (x86/vsyscall: Add a new vsyscall=xonly mode) merged at
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kernel v5.2-rc7 added constant XONLY to the anonymous enumeration type
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of variable vsyscall_mode, which made the value of constant NONE
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change from 1 to 2.
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This commit fixes the issue by checking the value of constant NONE
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using gdb's print command and typeof operator since there's no utility
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function to handle such anonymous enumeration type currently in crash
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utility.
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Signed-off-by: HATAYAMA Daisuke <d.hatayama@fujitsu.com>
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Signed-off-by: Lianbo Jiang <lijiang@redhat.com>
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---
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src/libgcore/gcore_x86.c | 56 ++++++++++++++++++++++++++++++++++++++--
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1 file changed, 54 insertions(+), 2 deletions(-)
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diff --git a/src/libgcore/gcore_x86.c b/src/libgcore/gcore_x86.c
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index 08e573c741f6..f334a85d4240 100644
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--- a/src/libgcore/gcore_x86.c
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+++ b/src/libgcore/gcore_x86.c
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@@ -41,6 +41,9 @@ struct gcore_x86_table
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static struct gcore_x86_table gcore_x86_table;
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struct gcore_x86_table *gxt = &gcore_x86_table;
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+static void gdb_run_command(char *cmd, char *buf, size_t size);
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+static int get_vsyscall_mode_none(void);
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+
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#ifdef X86_64
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static ulong gcore_x86_64_get_old_rsp(int cpu);
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static ulong gcore_x86_64_get_per_cpu__old_rsp(int cpu);
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@@ -2367,6 +2370,54 @@ int gcore_is_arch_32bit_emulation(struct task_context *tc)
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return FALSE;
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}
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+static void gdb_run_command(char *cmd, char *buf, size_t size)
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+{
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+ open_tmpfile();
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+ if (!gdb_pass_through(cmd,
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+ pc->tmpfile,
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+ GNU_RETURN_ON_ERROR)) {
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+ close_tmpfile();
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+ error(FATAL, "gdb command failed: %s", cmd);
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+ }
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+ rewind(pc->tmpfile);
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+ fgets(buf, size, pc->tmpfile);
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+ close_tmpfile();
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+}
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+
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+static int get_vsyscall_mode_none(void)
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+{
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+ static int none = -1;
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+ char cmd[32], buf[BUFSIZE];
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+ int i;
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+
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+ if (none != -1)
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+ return none;
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+
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+ /*
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+ * Variable vsyscall_mode is of anonymous enumeration
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+ * type. Because there's no utility function in crash utility
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+ * to get value of each constant in specified anonymous
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+ * enumeration type, we have no choice but rely on gdb's print
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+ * command in combination with typeof operator.
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+ */
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+ for (i = 0; i < 10; ++i) {
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+ snprintf(cmd, sizeof(cmd), "p (typeof(vsyscall_mode))%d", i);
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+ gdb_run_command(cmd, buf, sizeof(buf));
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+ if (strstr(buf, "NONE"))
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+ return none = i;
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+ }
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+
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+ /*
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+ * When the above logic doesn't work as expected, use 2, which
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+ * is the value on the definition where vsyscall_mode was
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+ * first introduced at the commit 3ae36655b97a (x86-64: Rework
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+ * vsyscall emulation and add vsyscall= parameter).
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+ */
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+ none = 2;
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+
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+ return none;
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+}
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+
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/**
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* Return an address to gate_vma.
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*/
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@@ -2377,7 +2428,8 @@ ulong gcore_arch_get_gate_vma(void)
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return 0UL;
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if (symbol_exists("vsyscall_mode")) {
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- enum { ENUMERATE, NONE } vsyscall_mode;
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+ int vsyscall_mode;
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+ int none = get_vsyscall_mode_none();
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readmem(symbol_value("vsyscall_mode"),
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KVADDR,
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@@ -2386,7 +2438,7 @@ ulong gcore_arch_get_gate_vma(void)
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"gcore_arch_get_gate_vma: vsyscall_mode",
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gcore_verbose_error_handle());
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- if (vsyscall_mode == NONE)
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+ if (vsyscall_mode == none)
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return 0UL;
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}
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--
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2.37.1
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