From 09635af7cdc14b7a9dc11010de4cb0d556e2a4a8 Mon Sep 17 00:00:00 2001 From: "Maciej W. Rozycki" Date: Tue, 9 Sep 2014 16:17:38 +0100 Subject: [PATCH] gdbserver-support: Handle gdbserver start failures As it happens we have a board that fails a gdb.base/gcore-relro.exp test case reproducibly and moreover the case appears to trigger a kernel bug making the it less than usable. Specifically the board remains responsive to some extent, however processes do not appear to be able to successfully complete termination anymore and perhaps more importantly further gdbserver processes can be started, but they never reach the stage of listening on the RSP socket. This change handles timeouts in gdbserver start properly, by throwing a TCL error exception when gdbserver does not report listening on the RSP socket in time. This is then caught at the outer level and reported, and 2 rather than 1 is returned so that the caller may tell the failure to start gdbserver and other issues apart and act accordingly (or do nothing). I thought letting the exception unwind further on might be a good idea for any test harnesses out there to break outright where a gdbserver start error is silently ignored right now, however I figured out the calls to gdbserver-support.exp are buried down too deep in the GDB test suite for such a change to be made easily. I think returning a distinct return value is good enough (the API says "non-zero", so 2 is as good as 1) and we can always make the error harder in a later step if required. With config/gdbserver.exp being used this change remains transparent to the target board, the return value is passed up by gdb_reload and the error exception unwinds through gdbserver_gdb_load and is caught and handled by mi_gdb_target_load. A call to perror is still made, reporting the timeout, and in the case of mi_gdb_target_load the procedure returns a value denoting unsuccessful completion. An unsuccessful completion of gdb_reload is already handled elsewhere. An alternative gdbserver board configuration can interpret the return value in its gdb_reload implementation and catch the error in gdbserver_gdb_load in an attempt to recover a target board that has gone astray, for example by rebooting the board somehow. This has proved effective with our failing board, that now completes the remaining test cases with no further hiccups. * lib/gdbserver-support.exp (gdbserver_start): Throw an error exception on timeout. (gdbserver_run): Catch any `gdbserver_spawn' error exceptions. (gdbserver_start_extended): Catch any `gdbserver_start' error exceptions. (gdbserver_start_multi, mi_gdbserver_start_multi): Likewise. * lib/mi-support.exp (mi_gdb_target_load): Catch any `gdbserver_gdb_load' error exceptions. --- gdb/testsuite/ChangeLog | 11 +++++++++++ gdb/testsuite/lib/gdbserver-support.exp | 26 ++++++++++++++++++++----- gdb/testsuite/lib/mi-support.exp | 5 ++++- 3 files changed, 36 insertions(+), 6 deletions(-) diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index 4d2933c4e1..0691c461b8 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,14 @@ +2014-09-09 Maciej W. Rozycki + + * lib/gdbserver-support.exp (gdbserver_start): Throw an error + exception on timeout. + (gdbserver_run): Catch any `gdbserver_spawn' error exceptions. + (gdbserver_start_extended): Catch any `gdbserver_start' error + exceptions. + (gdbserver_start_multi, mi_gdbserver_start_multi): Likewise. + * lib/mi-support.exp (mi_gdb_target_load): Catch any + `gdbserver_gdb_load' error exceptions. + 2014-09-09 Maciej W. Rozycki * lib/gdbserver-support.exp (gdbserver_start): Set timeout to diff --git a/gdb/testsuite/lib/gdbserver-support.exp b/gdb/testsuite/lib/gdbserver-support.exp index e3cae631b1..026a937ecc 100644 --- a/gdb/testsuite/lib/gdbserver-support.exp +++ b/gdb/testsuite/lib/gdbserver-support.exp @@ -287,6 +287,9 @@ proc gdbserver_start { options arguments } { continue } } + timeout { + error "Timeout waiting for gdbserver response." + } } break } @@ -326,7 +329,8 @@ proc gdbserver_spawn { child_args } { } # Start a gdbserver process running HOST_EXEC and pass CHILD_ARGS -# to it. Return 0 on success, or non-zero on failure. +# to it. Return 0 on success, or non-zero on failure: 2 if gdbserver +# failed to start or 1 if we couldn't connect to it. proc gdbserver_run { child_args } { global gdbserver_protocol @@ -347,7 +351,10 @@ proc gdbserver_run { child_args } { } } - set res [gdbserver_spawn $child_args] + if { [catch { gdbserver_spawn $child_args } res] == 1 } { + perror $res + return 2 + } set gdbserver_protocol [lindex $res 0] set gdbserver_gdbport [lindex $res 1] @@ -377,7 +384,10 @@ proc gdbserver_start_extended { } { global gdbserver_gdbport global use_gdb_stub - set res [gdbserver_start "--multi" ""] + if { [catch { gdbserver_start "--multi" "" } res] == 1 } { + perror $res + return 2 + } set gdbserver_protocol [lindex $res 0] if { [string first "extended-" $gdbserver_protocol] != 0} { set gdbserver_protocol "extended-$gdbserver_protocol" @@ -399,7 +409,10 @@ proc gdbserver_start_multi { } { global gdbserver_protocol global gdbserver_gdbport - set res [gdbserver_start "--multi" ""] + if { [catch { gdbserver_start "--multi" "" } res] == 1 } { + perror $res + return 2 + } set gdbserver_protocol [lindex $res 0] set gdbserver_gdbport [lindex $res 1] @@ -414,7 +427,10 @@ proc mi_gdbserver_start_multi { } { global gdbserver_protocol global gdbserver_gdbport - set res [gdbserver_start "--multi" ""] + if { [catch { gdbserver_start "--multi" "" } res] == 1 } { + perror $res + return 2 + } set gdbserver_protocol [lindex $res 0] set gdbserver_gdbport [lindex $res 1] diff --git a/gdb/testsuite/lib/mi-support.exp b/gdb/testsuite/lib/mi-support.exp index 204f1e8f01..a7f7aef4b9 100644 --- a/gdb/testsuite/lib/mi-support.exp +++ b/gdb/testsuite/lib/mi-support.exp @@ -477,7 +477,10 @@ proc mi_gdb_target_load { } { if { [info procs gdbserver_gdb_load] != "" } { mi_gdb_test "kill" ".*" "" - set res [gdbserver_gdb_load] + if { [catch gdbserver_gdb_load res] == 1 } { + perror $res + return -1 + } set protocol [lindex $res 0] set gdbport [lindex $res 1] -- 2.34.1