Date: Thu, 19 Apr 2018 05:06:56 +0000 (UTC) From: Andriy Gapon <avg@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r332752 - in head/sys: amd64/amd64 i386/i386 powerpc/powerpc sys Message-ID: <201804190506.w3J56vg9047202@repo.freebsd.org>
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Author: avg Date: Thu Apr 19 05:06:56 2018 New Revision: 332752 URL: https://svnweb.freebsd.org/changeset/base/332752 Log: set kdb_why to "trap" when calling kdb_trap from trap_fatal This will allow to hook a ddb script to "kdb.enter.trap" event. Previously there was no specific name for this event, so it could only be handled by either "kdb.enter.unknown" or "kdb.enter.default" hooks. Both are very unspecific. Having a specific event is useful because the fatal trap condition is very similar to panic but it has an additional property that the current stack frame is the frame where the trap occurred. So, both a register dump and a stack bottom dump have additional information that can help analyze the problem. I have added the event only on architectures that have trap_fatal() function defined. I haven't looked at other architectures. Their maintainers can add support for the event later. Sample script: kdb.enter.trap=bt; show reg; x/aS $rsp,20; x/agx $rsp,20 Reviewed by: kib, jhb, markj MFC after: 11 days Sponsored by: Panzura Differential Revision: https://reviews.freebsd.org/D15093 Modified: head/sys/amd64/amd64/trap.c head/sys/i386/i386/trap.c head/sys/powerpc/powerpc/trap.c head/sys/sys/kdb.h Modified: head/sys/amd64/amd64/trap.c ============================================================================== --- head/sys/amd64/amd64/trap.c Thu Apr 19 03:31:41 2018 (r332751) +++ head/sys/amd64/amd64/trap.c Thu Apr 19 05:06:56 2018 (r332752) @@ -761,6 +761,9 @@ trap_fatal(frame, eva) u_int type; struct soft_segment_descriptor softseg; char *msg; +#ifdef KDB + bool handled; +#endif code = frame->tf_err; type = frame->tf_trapno; @@ -811,9 +814,13 @@ trap_fatal(frame, eva) curproc->p_pid, curthread->td_name); #ifdef KDB - if (debugger_on_panic) - if (kdb_trap(type, 0, frame)) + if (debugger_on_panic) { + kdb_why = KDB_WHY_TRAP; + handled = kdb_trap(type, 0, frame); + kdb_why = KDB_WHY_UNSET; + if (handled) return; + } #endif printf("trap number = %d\n", type); if (type <= MAX_TRAP_MSG) Modified: head/sys/i386/i386/trap.c ============================================================================== --- head/sys/i386/i386/trap.c Thu Apr 19 03:31:41 2018 (r332751) +++ head/sys/i386/i386/trap.c Thu Apr 19 05:06:56 2018 (r332752) @@ -879,6 +879,9 @@ trap_fatal(frame, eva) int code, ss, esp; u_int type; struct soft_segment_descriptor softseg; +#ifdef KDB + bool handled; +#endif code = frame->tf_err; type = frame->tf_trapno; @@ -940,12 +943,13 @@ trap_fatal(frame, eva) #ifdef KDB if (debugger_on_panic) { + kdb_why = KDB_WHY_TRAP; frame->tf_err = eva; /* smuggle fault address to ddb */ - if (kdb_trap(type, 0, frame)) { - frame->tf_err = code; /* restore error code */ + handled = kdb_trap(type, 0, frame); + frame->tf_err = code; /* restore error code */ + kdb_why = KDB_WHY_UNSET; + if (handled) return; - } - frame->tf_err = code; /* restore error code */ } #endif printf("trap number = %d\n", type); Modified: head/sys/powerpc/powerpc/trap.c ============================================================================== --- head/sys/powerpc/powerpc/trap.c Thu Apr 19 03:31:41 2018 (r332751) +++ head/sys/powerpc/powerpc/trap.c Thu Apr 19 05:06:56 2018 (r332752) @@ -449,11 +449,19 @@ trap(struct trapframe *frame) static void trap_fatal(struct trapframe *frame) { +#ifdef KDB + bool handled; +#endif printtrap(frame->exc, frame, 1, (frame->srr1 & PSL_PR)); #ifdef KDB - if (debugger_on_panic && kdb_trap(frame->exc, 0, frame)) - return; + if (debugger_on_panic) { + kdb_why = KDB_WHY_TRAP; + handled = kdb_trap(frame->exc, 0, frame); + kdb_why = KDB_WHY_UNSET; + if (handled) + return; + } #endif panic("%s trap", trapname(frame->exc)); } Modified: head/sys/sys/kdb.h ============================================================================== --- head/sys/sys/kdb.h Thu Apr 19 03:31:41 2018 (r332751) +++ head/sys/sys/kdb.h Thu Apr 19 05:06:56 2018 (r332752) @@ -101,6 +101,7 @@ extern const char * volatile kdb_why; #define KDB_WHY_UNSET NULL /* No reason set. */ #define KDB_WHY_PANIC "panic" /* panic() was called. */ #define KDB_WHY_KASSERT "kassert" /* kassert failed. */ +#define KDB_WHY_TRAP "trap" /* Fatal trap. */ #define KDB_WHY_SYSCTL "sysctl" /* Sysctl entered debugger. */ #define KDB_WHY_BOOTFLAGS "bootflags" /* Boot flags were set. */ #define KDB_WHY_WITNESS "witness" /* Witness entered debugger. */
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