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[gdb/testsuite] Add xfail in gdb.arch/i386-pkru.exp

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On a x86_64-linux machine with pkru register, I run into:
...
(gdb) PASS: gdb.arch/i386-pkru.exp: set pkru value
info register pkru^M
pkru           0x12345678          305419896^M
(gdb) FAIL: gdb.arch/i386-pkru.exp: read value after setting value
...

This is a regression due to kernel commit e84ba47e313d ("x86/fpu: Hook up PKRU
onto ptrace()").  This is fixed by recent kernel commit 4a804c4f8356
("x86/fpu: Allow PKRU to be (once again) written by ptrace.").

The regression occurs for kernel versions v5.14-rc1 (the first tag containing
the regression) up to but excluding v6.2-rc1 (the first tag containing the fix).

Fix this by adding an xfail for the appropriate kernel versions.

Tested on x86_64-linux.

PR testsuite/29790
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29790
This commit is contained in:
Tom de Vries 2023-01-03 16:41:05 +01:00
parent 5aea5eca6c
commit b46632ca16
2 changed files with 88 additions and 4 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

45
gdb/testsuite/gdb.arch/i386-pkru.exp
View file

@ -58,6 +58,26 @@ if { !$supports_pkru } {
return
}
# Linux kernel versions 5.14.0 to 6.1.x contain a regression related to writing
# the PKRU using ptrace, see commit 4a804c4f8356 ("x86/fpu: Allow PKRU to be
# (once again) written by ptrace.").
set have_xfail 0
if { [istarget *-*-linux*] } {
set res [remote_exec target "uname -r"]
set status [lindex $res 0]
set output [lindex $res 1]
set re ^($decimal)\\.($decimal)\\.($decimal)
if { $status == 0
&& [regexp $re $output dummy v1 v2 v3] == 1 } {
set v [list $v1 $v2 $v3]
set have_xfail \
[expr \
[version_compare [list 5 14 0] <= $v] \
&& [version_compare $v < [list 6 2 0]]]
}
}
# Test pkru register at startup
gdb_test "print /x \$pkru" "= $default_pkru_re" "pkru register"
@ -65,11 +85,28 @@ gdb_test "print /x \$pkru" "= $default_pkru_re" "pkru register"
gdb_breakpoint [ gdb_get_line_number "break here 1" ]
gdb_continue_to_breakpoint "break here 1" ".*break here 1.*"
gdb_test "info register pkru" ".*pkru.*0x12345678.*" "read pkru register"
gdb_test "print /x \$pkru = 0x44444444" "= 0x44444444" "set pkru value"
gdb_test "info register pkru" ".*pkru.*0x44444444.*" "read value after setting value"
set val1 0x12345678
gdb_test "info register pkru" ".*pkru.*$val1.*" "read pkru register"
set val2 0x44444444
gdb_test "print /x \$pkru = $val2" "= $val2" "set pkru value"
set xval $val2
gdb_test_multiple "info register pkru" "read value after setting value" {
-re -wrap ".*pkru.*$val2.*" {
pass $gdb_test_name
}
-re -wrap ".*pkru.*$val1.*" {
if { $have_xfail } {
xfail $gdb_test_name
} else {
fail $gdb_test_name
}
set xval $val1
}
}
gdb_breakpoint [ gdb_get_line_number "break here 2" ]
gdb_continue_to_breakpoint "break here 2" ".*break here 2.*"
gdb_test "print /x rd_value" "= 0x44444444" "variable after reading pkru"
gdb_test "print /x rd_value" "= $xval" "variable after reading pkru"

47
gdb/testsuite/lib/gdb-utils.exp
View file

@ -100,3 +100,50 @@ proc gdb_get_bp_addr { num } {
}
return ""
}
# Compare the version numbers in L1 to those in L2 using OP, and return
# 1 if the comparison is true.
proc version_compare { l1 op l2 } {
set len [llength $l1]
if { $len != [llength $l2] } {
error "l2 not the same length as l1"
}
switch -exact $op {
"==" -
"<" {}
"<=" { return [expr [version_compare $l1 < $l2] \
|| [version_compare $l1 == $l2]]}
default { error "unsupported op: $op" }
}
# Handle ops < and ==.
set idx 0
foreach v1 $l1 {
set v2 [lindex $l2 $idx]
incr idx
set last [expr $len == $idx]
set cmp [expr $v1 $op $v2]
if { $op == "==" } {
if { $cmp } {
continue
} else {
return 0
}
} else {
# $op == "<".
if { $cmp } {
return 1
} else {
if { !$last && $v1 == $v2 } {
continue
}
return 0
}
}
}
return 1
}