[DragonFlyBSD - Bug #911] (In Progress) kldload/kernel linker can exceed malloc reserve and panic system

[bugtracker-admin at leaf.dragonflybsd.org]

Issue #911 has been updated by tuxillo.

Status changed from New to In Progress
Assignee changed from corecode to tuxillo
Target version set to 3.8.0

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Bug #911: kldload/kernel linker can exceed malloc reserve and panic system
http://bugs.dragonflybsd.org/issues/911#change-11786

* Author: corecode
* Status: In Progress
* Priority: Normal
* Assignee: tuxillo
* Category: Kernel
* Target version: 3.8.0
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hey,

I just booted with hw.physmem=64m and got a panic when trying to load a module:

panic: kld: malloc limit exceeded

(kgdb) bt
#0  dumpsys () at thread.h:83
#1  0xc018450c in boot (howto=256) at /usr/build/src/sys/kern/kern_shutdown.c:375
#2  0xc0184661 in panic (fmt=Variable "fmt" is not available.
) at /usr/build/src/sys/kern/kern_shutdown.c:800
#3  0xc0182129 in kmalloc (size=78, type=0xc02f5600, flags=2)
    at /usr/build/src/sys/kern/kern_slaballoc.c:445
#4  0xc01678b4 in linker_make_file (pathname=0xc641b000 "./nvidia.ko", priv=0xc63ea028, 
    ops=0xc02f5bc8) at /usr/build/src/sys/kern/kern_linker.c:369
#5  0xc016a773 in link_elf_load_module (filename=0xc641b000 "./nvidia.ko", result=0xc83efc7c)
    at /usr/build/src/sys/kern/link_elf.c:604
#6  0xc01684e0 in linker_load_file (filename=0xc641b000 "./nvidia.ko", result=0xc83efca8)
    at /usr/build/src/sys/kern/kern_linker.c:272
#7  0xc016871c in sys_kldload (uap=0xc83efcf0) at /usr/build/src/sys/kern/kern_linker.c:724

the problem seems to be that M_LINKER already used 10% of all memory (allegedly).  In this case kmalloc() simply panics if passing M_WAITOK without M_NULLOK.  This is quite unfortunate.  Shouldn't we try to stay alive and print a warning and block, hoping that the problem will resolve itself?

cheers
  simon



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