Gerrit Nagelhout
2004-Mar-11 11:02 UTC
kernel panic using kqueue with EVFILT_TIMER and timeout 0
Hi,
We have been getting some kernel panics while using kqueue, and have
narrowed it down to a simple program. Running the following will cause a
kernel panic (and sometimes a hang) almost immediately on 4.7 STABLE. It
does not seem to cause any problems on 5.2, but we haven't done much testing
on it. Key seems to be using the timeout of 0, although I don't know if
that is a requirement. I am going to start looking into the code to see
what could cause this, but I'd like to know if anyone has seen this before.
Thanks,
Gerrit
#include <sys/types.h>
#include <sys/event.h>
int main()
{
int i;
struct kevent ev[4096];
int kq = kqueue();
for (i = 0; i < 4096; ++i)
{
EV_SET(ev + i, i, EVFILT_TIMER, EV_ADD, 0, 0, 0);
}
kevent(kq, ev, 4096, 0, 0, 0);
return 0;
}
SMP 2 cpus
IdlePTD at phsyical address 0x00439000
initial pcb at physical address 0x003793a0
panicstr: page fault
panic messages:
---
Fatal trap 12: page fault while in kernel mode
mp_lock = 00000003; cpuid = 0; lapic.id = 00000000
fault virtual address = 0x14
fault code = supervisor read, page not present
instruction pointer = 0x8:0xc01c5f53
stack pointer = 0x10:0xe03badd0
frame pointer = 0x10:0xe03baddc
code segment = base 0x0, limit 0xfffff, type 0x1b
= DPL 0, pres 1, def32 1, gran 1
processor eflags = interrupt enabled, resume, IOPL = 0
current process = 2386 (kqueue)
interrupt mask = net tty bio cam <- SMP: XXX
trap number = 12
panic: page fault
mp_lock = 00000003; cpuid = 0; lapic.id = 00000000
boot() called on cpu#0
syncing disks... 21 21 21 21 21 21 21 21 21 21 21 21 21 21 21 21 21 21 21 21
giving up on 21 buffers
Uptime: 10m26s
dumping to dev #da/0x30001, offset 2098176
dump 1023 1022 1021 1020 1019 1018 1017 1016 1015 1014 1013 1012 1011 1010
1009 1008 1007 1006 1005 1004 1003 1002 1001 1000 999 998 997 996 995 994
993 992 991 990 989 988 987 986 985 984 983 982 981 980 979 978 977 976 975
974 973 972 971 970 969 968 967 966 965 964 963 962 961 960 959 958 957 956
955 954 953 952 951 950 949 948 947 946 945 944 943 942 941 940 939 938 937
936 935 934 933 932 931 930 929 928 927 926 925 924 923 922 921 920 919 918
917 916 915 914 913 912 911 910 909 908 907 906 905 904 903 902 901 900 899
898 897 896 895 894 893 892 891 890 889 888 887 886 885 884 883 882 881 880
879 878 877 876 875 874 873 872 871 870 869 868 867 866 865 864 863 862 861
860 859 858 857 856 855 854 853 852 851 850 849 848 847 846 845 844 843 842
841 840 839 838 837 836 835 834 833 832 831 830 829 828 827 826 825 824 823
822 821 820 819 818 817 816 815 814 813 812 811 810 809 808 807 806 805 804
803 802 801 800 799 798 797 796 795 794 793 792 791 790 789 788 787 786 785
784 783 782 781 780 779 778 777 776 775 774 773 772 771 770 769 768 767 766
765 764 763 762 761 760 759 758 757 756 755 754 753 752 751 750 749 748 747
746 745 744 743 742 741 740 739 738 737 736 735 734 733 732 731 730 729 728
727 726 725 724 723 722 721 720 719 718 717 716 715 714 713 712 711 710 709
708 707 706 705 704 703 702 701 700 699 698 697 696 695 694 693 692 691 690
689 688 687 686 685 684 683 682 681 680 679 678 677 676 675 674 673 672 671
670 669 668 667 666 665 664 663 662 661 660 659 658 657 656 655 654 653 652
651 650 649 648 647 646 645 644 643 642 641 640 639 638 637 636 635 634 633
632 631 630 629 628 627 626 625 624 623 622 621 620 619 618 617 616 615 614
613 612 611 610 609 608 607 606 605 604 603 602 601 600 599 598 597 596 595
594 593 592 591 590 589 588 587 586 585 584 583 582 581 580 579 578 577 576
575 574 573 572 571 570 569 568 567 566 565 564 563 562 561 560 559 558 557
556 555 554 553 552 551 550 549 548 547 546 545 544 543 542 541 540 539 538
537 536 535 534 533 532 531 530 529 528 527 526 525 524 523 522 521 520 519
518 517 516 515 514 513 512 511 510 509 508 507 506 505 504 503 502 501 500
499 498 497 496 495 494 493 492 491 490 489 488 487 486 485 484 483 482 481
480 479 478 477 476 475 474 473 472 471 470 469 468 467 466 465 464 463 462
461 460 459 458 457 456 455 454 453 452 451 450 449 448 447 446 445 444 443
442 441 440 439 438 437 436 435 434 433 432 431 430 429 428 427 426 425 424
423 422 421 420 419 418 417 416 415 414 413 412 411 410 409 408 407 406 405
404 403 402 401 400 399 398 397 396 395 394 393 392 391 390 389 388 387 386
385 384 383 382 381 380 379 378 377 376 375 374 373 372 371 370 369 368 367
366 365 364 363 362 361 360 359 358 357 356 355 354 353 352 351 350 349 348
347 346 345 344 343 342 341 340 339 338 337 336 335 334 333 332 331 330 329
328 327 326 325 324 323 322 321 320 319 318 317 316 315 314 313 312 311 310
309 308 307 306 305 304 303 302 301 300 299 298 297 296 295 294 293 292 291
290 289 288 287 286 285 284 283 282 281 280 279 278 277 276 275 274 273 272
271 270 269 268 267 266 265 264 263 262 261 260 259 258 257 256 255 254 253
252 251 250 249 248 247 246 245 244 243 242 241 240 239 238 237 236 235 234
233 232 231 230 229 228 227 226 225 224 223 222 221 220 219 218 217 216 215
214 213 212 211 210 209 208 207 206 205 204 203 202 201 200 199 198 197 196
195 194 193 192 191 190 189 188 187 186 185 184 183 182 181 180 179 178 177
176 175 174 173 172 171 170 169 168 167 166 165 164 163 162 161 160 159 158
157 156 155 154 153 152 151 150 149 148 147 146 145 144 143 142 141 140 139
138 137 136 135 134 133 132 131 130 129 128 127 126 125 124 123 122 121 120
119 118 117 116 115 114 113 112 111 110 109 108 107 106 105 104 103 102 101
100 99 98 97 96 95 94 93 92 91 90 89 88 87 86 85 84 83 82 81 80 79 78 77 76
75 74 73 72 71 70 69 68 67 66 65 64 63 62 61 60 59 58 57 56 55 54 53 52 51
50 49 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26
25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
---
#0 dumpsys () at /usr/src/sys/kern/kern_shutdown.c:492
492 /usr/src/sys/kern/kern_shutdown.c: No such file or directory.
(kgdb) bt
#0 dumpsys () at /usr/src/sys/kern/kern_shutdown.c:492
#1 0xc01bef28 in boot (howto=256) at /usr/src/sys/kern/kern_shutdown.c:321
#2 0xc01bf451 in panic (fmt=0xc033e439 "%s")
at /usr/src/sys/kern/kern_shutdown.c:607
#3 0xc02e5ade in trap_fatal (frame=0xe03bad90, eva=20)
at /usr/src/sys/i386/i386/trap.c:992
#4 0xc02e570d in trap_pfault (frame=0xe03bad90, usermode=0, eva=20)
at /usr/src/sys/i386/i386/trap.c:885
#5 0xc02e51af in trap (frame={tf_fs = -533004264, tf_es = -678035440,
tf_ds = 720912, tf_edi = 1073741824, tf_esi = 1, tf_ebp = -532959780,
tf_isp = -532959812, tf_ebx = 0, tf_edx = 1, tf_ecx = 0,
tf_eax = 1073741824, tf_trapno = 12, tf_err = 0, tf_eip = -1071882413,
tf_cs = 8, tf_eflags = 66067, tf_esp = -531521856, tf_ss -1071957392})
at /usr/src/sys/i386/i386/trap.c:484
#6 0xc01c5f53 in callout_reset (c=0x0, to_ticks=1,
ftn=0xc01b3a70 <filt_timerexpire>, arg=0xe0519ec0)
at /usr/src/sys/kern/kern_timeout.c:244
#7 0xc01b3aeb in filt_timerexpire (knx=0xe0519ec0)
at /usr/src/sys/kern/kern_event.c:294
#8 0xc01c5e4e in softclock () at /usr/src/sys/kern/kern_timeout.c:140
#9 0xc02d46cb in doreti_swi ()
#10 0xc01b3b7b in filt_timerattach (kn=0xe0519ec0)
at /usr/src/sys/kern/kern_event.c:320
---Type <return> to continue, or q <return> to quit---
#11 0xc01b4034 in kqueue_register (kq=0xc35fd500, kev=0xc35fd570,
p=0xdc34f8e0)
at /usr/src/sys/kern/kern_event.c:529
#12 0xc01b3d74 in kevent (p=0xdc34f8e0, uap=0xe03baf80)
at /usr/src/sys/kern/kern_event.c:414
#13 0xc02e5e2d in syscall2 (frame={tf_fs = 47, tf_es = 47, tf_ds = 47,
tf_edi = -1077936956, tf_esi = -1077936948, tf_ebp = -1077937040,
tf_isp = -532959276, tf_ebx = 1, tf_edx = 4096, tf_ecx = 3,
tf_eax = 363, tf_trapno = 12, tf_err = 2, tf_eip = 1745495508,
tf_cs = 31, tf_eflags = 663, tf_esp = -1078019004, tf_ss = 47})
at /usr/src/sys/i386/i386/trap.c:1193
#14 0xc02d061b in Xint0x80_syscall ()
#15 0x8048472 in ?? ()
Gerrit Nagelhout
Senior Software Engineer
Sandvine Incorporated
Direct: +1 (519) 880 2400 x2706
> www.sandvine.com
Gerrit Nagelhout
2004-Mar-11 14:24 UTC
kernel panic using kqueue with EVFILT_TIMER and timeout 0
>> Hi,>> We have been getting some kernel panics while using kqueue, and have >> narrowed it down to a simple program.I have found the problem. There is a race condition in kern_event.c. I have submitted the following patch: http://www.freebsd.org/cgi/query-pr.cgi?pr=64121