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(a)sonymobile.com sonymobile.com -- Crash-utility mailing list Crash-utility(a)redhat.com https://www.redhat.com/mailman/listinfo/crash-utility

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

Jan Karlsson Senior Software Engineer System Assurance Sony Mobile Communications Tel: +46 703 062 174 jan.karlsson(a)sonymobile.com sonymobile.com -----Original Message----- From: crash-utility-bounces(a)redhat.com [mailto:crash-utility-bounces@redhat.com] 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-utility] 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(a)sonymobile.com > > > > sonymobile.com > > > > > > > > -- > Crash-utility mailing list > Crash-utility(a)redhat.com > https://www.redhat.com/mailman/listinfo/crash-utility -- Crash-utility mailing list Crash-utility(a)redhat.com https://www.redhat.com/mailman/listinfo/crash-utility

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(a)sonymobile.com sonymobile.com -----Original Message----- From: crash-utility-bounces(a)redhat.com [mailto:crash-utility-bounces@redhat.com] 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-utility] 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/a3a441aeabd6c5c3c86b4793a28... 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(a)sonymobile.com > > sonymobile.com > > > > -----Original Message----- > From: crash-utility-bounces(a)redhat.com > [mailto:crash-utility-bounces@redhat.com] 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-utility] 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(a)sonymobile.com > > > > > > > > sonymobile.com > > > > > > > > > > > > > > > > -- > > Crash-utility mailing list > > Crash-utility(a)redhat.com > > https://www.redhat.com/mailman/listinfo/crash-utility > > -- > Crash-utility mailing list > Crash-utility(a)redhat.com > https://www.redhat.com/mailman/listinfo/crash-utility > -- Crash-utility mailing list Crash-utility(a)redhat.com https://www.redhat.com/mailman/listinfo/crash-utility -- Crash-utility mailing list Crash-utility(a)redhat.com https://www.redhat.com/mailman/listinfo/crash-utility