The fix from ba773f7c510c0b252145933926c636c439889207 (x86,kgdb: Fix hw breakpoint regression) was not entirely complete.
The kgdb_remove_all_hw_break() function also needs to call the hw_break_release_slot() or else a breakpoint can get activated again after the debugger has detached. The kgdb test suite exposes the behavior in the form of either a hang or repetitive failure. The kernel config that exposes the problem contains all of the following: CONFIG_DEBUG_RODATA=y CONFIG_KGDB_TESTS=y CONFIG_KGDB_TESTS_ON_BOOT=y CONFIG_KGDB_TESTS_BOOT_STRING="V1F100" Reported-by: Frederic Weisbecker <[email protected]> Signed-off-by: Jason Wessel <[email protected]> Tested-by: Frederic Weisbecker <[email protected]> --- arch/x86/kernel/kgdb.c | 12 ++++++++---- 1 files changed, 8 insertions(+), 4 deletions(-) diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c index ec592ca..cd21b65 100644 --- a/arch/x86/kernel/kgdb.c +++ b/arch/x86/kernel/kgdb.c @@ -315,14 +315,18 @@ static void kgdb_remove_all_hw_break(void) if (!breakinfo[i].enabled) continue; bp = *per_cpu_ptr(breakinfo[i].pev, cpu); - if (bp->attr.disabled == 1) + if (!bp->attr.disabled) { + arch_uninstall_hw_breakpoint(bp); + bp->attr.disabled = 1; continue; + } if (dbg_is_early) early_dr7 &= ~encode_dr7(i, breakinfo[i].len, breakinfo[i].type); - else - arch_uninstall_hw_breakpoint(bp); - bp->attr.disabled = 1; + else if (hw_break_release_slot(i)) + printk(KERN_ERR "KGDB: hw bpt remove failed %lx\n", + breakinfo[i].addr); + breakinfo[i].enabled = 0; } } -- 1.7.0.4 ------------------------------------------------------------------------------ Beautiful is writing same markup. Internet Explorer 9 supports standards for HTML5, CSS3, SVG 1.1, ECMAScript5, and DOM L2 & L3. Spend less time writing and rewriting code and more time creating great experiences on the web. Be a part of the beta today http://p.sf.net/sfu/msIE9-sfdev2dev _______________________________________________ Kgdb-bugreport mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/kgdb-bugreport
