From 4a6a1ed4a113d386b131938bbc7d66e7b495e73f Mon Sep 17 00:00:00 2001 From: Yao Qi Date: Thu, 28 Jan 2016 14:16:42 +0000 Subject: [PATCH] Fix GDB crash in dprintf.exp I see GDB crashes in dprintf.exp on aarch64-linux testing, (gdb) PASS: gdb.base/dprintf.exp: agent: break 29 set dprintf-style agent^M (gdb) PASS: gdb.base/dprintf.exp: agent: set dprintf style to agent continue^M Continuing. ASAN:SIGSEGV ================================================================= ==22475==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000008 (pc 0x000000494820 sp 0x7fff389b83a0 bp 0x62d000082417 T0) #0 0x49481f in remote_add_target_side_commands /home/yao/SourceCode/gnu/gdb/git/gdb/remote.c:9190^M #1 0x49e576 in remote_add_target_side_commands /home/yao/SourceCode/gnu/gdb/git/gdb/remote.c:9174^M #2 0x49e576 in remote_insert_breakpoint /home/yao/SourceCode/gnu/gdb/git/gdb/remote.c:9240^M #3 0x5278b7 in insert_bp_location /home/yao/SourceCode/gnu/gdb/git/gdb/breakpoint.c:2734^M #4 0x52ac09 in insert_breakpoint_locations /home/yao/SourceCode/gnu/gdb/git/gdb/breakpoint.c:3159^M #5 0x52ac09 in update_global_location_list /home/yao/SourceCode/gnu/gdb/git/gdb/breakpoint.c:12686 the root cause of this problem in this case is about linespec and symtab which produces additional incorrect location and a NULL is added to bp_tgt->tcommands. I posted a patch https://sourceware.org/ml/gdb-patches/2015-12/msg00321.html to fix it in linespec (the fix causes regression), but GDB still shouldn't add NULL into bp_tgt->tcommands. The logic of build_target_command_list looks odd to me. If we get something wrong in parse_cmd_to_aexpr (it returns NULL), we shouldn't continue, instead we should set flag null_command_or_parse_error. This is what this patch does. In the meantime, we find build_target_condition_list has the same problem, so fix it too. gdb: 2016-01-28 Yao Qi * breakpoint.c (build_target_command_list): Don't call continue if aexpr is NULL. (build_target_condition_list): Likewise. --- gdb/ChangeLog | 6 ++++++ gdb/breakpoint.c | 9 --------- 2 files changed, 6 insertions(+), 9 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 0958c5b2c7..065319c9bd 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,9 @@ +2016-01-28 Yao Qi + + * breakpoint.c (build_target_command_list): Don't call continue + if aexpr is NULL. + (build_target_condition_list): Likewise. + 2016-01-27 Kevin Buettner * rx-tdep.c (rx_push_dummy_call): Treat scalars larger than 8 diff --git a/gdb/breakpoint.c b/gdb/breakpoint.c index 7b610ef28d..afd9065193 100644 --- a/gdb/breakpoint.c +++ b/gdb/breakpoint.c @@ -2347,12 +2347,6 @@ build_target_condition_list (struct bp_location *bl) need to parse the condition to bytecodes again. */ aexpr = parse_cond_to_aexpr (bl->address, loc->cond); loc->cond_bytecode = aexpr; - - /* Check if we managed to parse the conditional expression - correctly. If not, we will not send this condition - to the target. */ - if (aexpr) - continue; } /* If we have a NULL bytecode expression, it means something @@ -2553,9 +2547,6 @@ build_target_command_list (struct bp_location *bl) aexpr = parse_cmd_to_aexpr (bl->address, loc->owner->extra_string); loc->cmd_bytecode = aexpr; - - if (!aexpr) - continue; } /* If we have a NULL bytecode expression, it means something