Fine. If you remove that message then I see no problems with your patch. Jan Jan Karlsson Senior Software Engineer System Assurance Sony Mobile Communications Tel: +46 703 062 174 jan.karlsson@xxxxxxxxxxxxxx sonymobile.com -----Original Message----- From: crash-utility-bounces@xxxxxxxxxx [mailto:crash-utility-bounces@xxxxxxxxxx] On Behalf Of Dave Anderson Sent: den 22 oktober 2014 15:02 To: Discussion list for crash utility usage, maintenance and development Subject: Re: Crash in crash ----- Original Message ----- > Hi > > Your patch works but I get a "strange" error message: > > please wait... (determining panic task) > bt: bsearch for tgid failed: task: ffffffc01cfed400 tgid: 5040 > > KERNEL: vmlinux > DUMPFILE: vmcore > .... > > This message does not occur with my patch. > > Jan Yeah, that message will be removed in crash-7.0.9: https://github.com/crash-utility/crash/commit/a3a441aeabd6c5c3c86b4793a283927507a5cc10 The point of the matter is to entirely avoid doing initial sort, and then doing the RSS gathering and associated readmem()'s for all tasks during the last-ditch panic-task search that your dumpfile requires. Dave > > Jan Karlsson > Senior Software Engineer > System Assurance > > Sony Mobile Communications > Tel: +46 703 062 174 > jan.karlsson@xxxxxxxxxxxxxx > > sonymobile.com > > > > -----Original Message----- > From: crash-utility-bounces@xxxxxxxxxx > [mailto:crash-utility-bounces@xxxxxxxxxx] On Behalf Of Dave Anderson > Sent: den 21 oktober 2014 16:32 > To: Discussion list for crash utility usage, maintenance and > development > Subject: Re: Crash in crash > > > Hi Jan, > > Good catch. As far as a fix goes, it would be more efficient if > tgid_quick_search() just returns a NULL in that case. Try the > attached patch. > > Thanks, > Dave > > > > > ----- Original Message ----- > > > > > > Hi Dave > > > > > > > > I have a vmcore file for ARM64 that crashes Crash during startup. > > The core file is created at a hardware watchdog (I believe) so there > > is no panic message or something similar in the log. > > > > > > > > This is the printout from Crash running under gdb, after the > > copyrights and config information: > > > > > > > > please wait... (determining panic task) > > > > Program received signal SIGSEGV, Segmentation fault. > > > > 0x000000000047ed40 in tgid_quick_search (tgid=5040) at memory.c:4114 > > > > 4114 if (tgid == last->tgid) { > > > > > > > > (gdb) bt > > > > #0 0x000000000047ed40 in tgid_quick_search (tgid=5040) at > > memory.c:4114 > > > > #1 0x000000000047f046 in get_task_mem_usage > > (task=18446743799318107136, > > tm=0x7fffffff6f40) > > > > at memory.c:4186 > > > > #2 0x000000000047c679 in vm_area_dump (task=18446743799318107136, > > flag=10, vaddr=0, ref=0x0) > > > > at memory.c:3671 > > > > #3 0x000000000047ec08 in in_user_stack (task=18446743799318107136, > > vaddr=0) at memory.c:4063 > > > > #4 0x00000000004fd9fe in arm64_get_dumpfile_stackframe > > (frame=<synthetic > > pointer>, > > > > bt=<optimized out>) at arm64.c:1077 > > > > #5 arm64_get_stack_frame (bt=0x7fffffffc690, pcp=0x7fffffff9560, > > spp=0x7fffffff9568) > > > > at arm64.c:1103 > > > > #6 0x00000000004de409 in back_trace (bt=0x7fffffffc690) at > > kernel.c:2533 > > > > #7 0x00000000004d1563 in foreach (fd=0x7fffffffc7c0) at task.c:6161 > > > > #8 0x00000000004d2bbd in panic_search () at task.c:6425 > > > > #9 0x00000000004d4454 in get_panic_context () at task.c:5364 > > > > #10 task_init () at task.c:491 > > > > #11 0x000000000046146e in main_loop () at main.c:801 > > > > #12 0x00000000006467a3 in captured_command_loop (data=<optimized > > out>) at > > main.c:258 > > > > #13 0x000000000064535b in catch_errors (func=0x646790 > > <captured_command_loop>, func_args=0x0, > > > > errstring=0x873235 "", mask=6) at exceptions.c:557 > > > > #14 0x0000000000647726 in captured_main (data=<optimized out>) at > > main.c:1064 > > > > #15 0x000000000064535b in catch_errors (func=0x646aa0 > > <captured_main>, func_args=0x7fffffffe030, > > > > errstring=0x873235 "", mask=6) at exceptions.c:557 > > > > #16 0x0000000000647a84 in gdb_main (args=<optimized out>) at > > main.c:1079 > > > > #17 0x0000000000647abe in gdb_main_entry (argc=<optimized out>, > > argv=<optimized out>) > > > > at main.c:1099 > > > > #18 0x000000000045f61f in main (argc=3, argv=0x7fffffffe188) at > > main.c:758 > > > > > > > > (gdb) p tt->last_tgid > > > > $1 = (struct tgid_context *) 0x0 > > > > > > > > Source code for tgid_quick_search: > > > > static struct tgid_context * > > > > tgid_quick_search(ulong tgid) > > > > { > > > > struct tgid_context *last, *next; > > > > > > > > tt->tgid_searches++; > > > > > > > > last = tt->last_tgid; > > > > if (tgid == last->tgid) { > > > > tt->tgid_cache_hits++; > > > > return last; > > > > } > > > > .... > > > > } > > > > > > > > So 'last' becomes 0 which causes the crash. > > > > > > > > After some more investigation I have seen that "tt->last_tgid" is > > initialized in function sort_tgid_array in task.c, but that function > > seems to be called at a later stage. > > > > > > > > By adding a line in tgid_quick_search: > > > > > > > > static struct tgid_context * > > > > tgid_quick_search(ulong tgid) > > > > { > > > > struct tgid_context *last, *next; > > > > > > > > tt->tgid_searches++; > > > > > > > > if (tt->last_tgid == 0) sort_tgid_array(); // added line > > > > last = tt->last_tgid; > > > > if (tgid == last->tgid) { > > > > tt->tgid_cache_hits++; > > > > return last; > > > > } > > > > ... > > > > > > > > I can run Crash on this core file. However I do not know if this is > > the best way to fix the problem. > > > > > > > > Jan > > > > > > > > Jan Karlsson > > > > Senior Software Engineer > > > > System Assurance > > > > > > > > Sony Mobile Communications > > > > Tel: +46 703 062 174 > > > > jan.karlsson@xxxxxxxxxxxxxx > > > > > > > > sonymobile.com > > > > > > > > > > > > > > > > -- > > Crash-utility mailing list > > Crash-utility@xxxxxxxxxx > > https://www.redhat.com/mailman/listinfo/crash-utility > > -- > Crash-utility mailing list > Crash-utility@xxxxxxxxxx > https://www.redhat.com/mailman/listinfo/crash-utility > -- Crash-utility mailing list Crash-utility@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/crash-utility -- Crash-utility mailing list Crash-utility@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/crash-utility
