Re: kern/48550: panic when accessing CDs

[Martin Husemann <martin%duskware.de@localhost>]

The following reply was made to PR kern/48550; it has been noted by GNATS.

From: Martin Husemann <martin%duskware.de@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: 
Subject: Re: kern/48550: panic when accessing CDs
Date: Wed, 29 Jan 2014 20:50:54 +0100

 Here is a better backtrace:
 
 #3  0xffffffff80750333 in buf_mempoolidx (size=<optimized out>, 
     size@entry=1572864) at ../../../../kern/vfs_bio.c:607
 #4  0xffffffff80752c43 in buf_roundsize (size=1572864)
     at ../../../../kern/vfs_bio.c:615
 #5  allocbuf (bp=bp@entry=0xfffffe813695eb48, size=size@entry=1572864, 
     preserve=preserve@entry=0) at ../../../../kern/vfs_bio.c:1245
 #6  0xffffffff8075306b in geteblk (size=1572864)
     at ../../../../kern/vfs_bio.c:1224
 #7  0xffffffff8065d5e2 in readdisklabel (dev=1539, 
     strat=strat@entry=0xffffffff80221391 <cdstrategy>, 
     lp=lp@entry=0xfffffe8136e0d8c0, osdep=osdep@entry=0xfffffe81070e3800)
     at ../../../../kern/subr_disk_mbr.c:435
 #8  0xffffffff80221d4d in cdgetdisklabel (cd=cd@entry=0xfffffe8136e0da80)
     at ../../../../dev/scsipi/cd.c:1766
 
 611     static u_long
 612     buf_roundsize(u_long size)
 613     {
 614             /* Round up to nearest power of 2 */
 615             return (1 << (buf_mempoolidx(size) + MEMPOOL_INDEX_OFFSET));
 616     }
 
 (gdb) p/x size
 $6 = 0x180000
 
 
 and a few frames below:
 #7  0xffffffff8065d5e2 in readdisklabel (dev=1539, 
     strat=strat@entry=0xffffffff80221391 <cdstrategy>, 
     lp=lp@entry=0xfffffe8136e0d8c0, osdep=osdep@entry=0xfffffe81070e3800)
     at ../../../../kern/subr_disk_mbr.c:435
 435             a.bp = geteblk(SCANBLOCKS * (int)lp->d_secsize);
 
 (gdb) p *lp
 $10 = {d_magic = 2186691927, d_type = 13, d_subtype = 0, 
   d_typename = "optical media\000\000", d_un = {
     un_d_packname = "fictitious\000\000\000\000\000", un_b = {
       un_d_boot0 = 0x6f69746974636966 <Address 0x6f69746974636966 out of 
bounds>, un_d_boot1 = 0x7375 <Address 0x7375 out of bounds>}, 
     un_d_pad = 8028075807037679974}, d_secsize = 524288, d_nsectors = 100, 
   d_ntracks = 1, d_ncylinders = 255355, d_secpercyl = 100, 
   d_secperunit = 25535489, d_sparespertrack = 0, d_sparespercyl = 0, 
   d_acylinders = 0, d_rpm = 300, d_interleave = 1, d_trackskew = 0, 
   d_cylskew = 0, d_headswitch = 0, d_trkseek = 0, d_flags = 33, d_drivedata = {
     0, 0, 0, 0, 0}, d_spare = {0, 0, 0, 0, 0}, d_magic2 = 2186691927, 
   d_checksum = 24808, d_npartitions = 4, d_bbsize = 0, d_sbsize = 0, 
   d_partitions = {{p_size = 25535489, p_offset = 0, __partition_u2 = {
         fsize = 0, cdsession = 0}, p_fstype = 7 '\a', p_frag = 0 '\000', 
       __partition_u1 = {cpg = 0, sgs = 0}}, {p_size = 0, p_offset = 0, 
       __partition_u2 = {fsize = 0, cdsession = 0}, p_fstype = 0 '\000', 
       p_frag = 0 '\000', __partition_u1 = {cpg = 0, sgs = 0}}, {p_size = 0, 
       p_offset = 0, __partition_u2 = {fsize = 0, cdsession = 0}, 
       p_fstype = 0 '\000', p_frag = 0 '\000', __partition_u1 = {cpg = 0, 
         sgs = 0}}, {p_size = 25535489, p_offset = 0, __partition_u2 = {
         fsize = 0, cdsession = 0}, p_fstype = 24 '\030', p_frag = 0 '\000', 
       __partition_u1 = {cpg = 0, sgs = 0}}, {p_size = 0, p_offset = 0, 
       __partition_u2 = {fsize = 0, cdsession = 0}, p_fstype = 0 '\000', 
       p_frag = 0 '\000', __partition_u1 = {cpg = 0, 
         sgs = 0}} <repeats 12 times>}}
 
 
 So it seems the generation of the fictious label has gone awfully wrong.
 The medium is some random NetBSD/alpha install medium in this case.
 
 Hardware in question:
 
 ahcisata0 at pci0 dev 31 function 2: vendor 0x8086 product 0x3b29 (rev. 0x05)
 ahcisata0: interrupting at ioapic0 pin 19
 ahcisata0: 64-bit DMA
 ahcisata0: AHCI revision 1.30, 4 ports, 32 slots, CAP 
0xff20ff63<SXS,EMS,PSC,SSC
 ,PMD,ISS=0x2=Gen2,SCLO,SAL,SALP,SSS,SMPS,SSNTF,SNCQ,S64A>
 atabus0 at ahcisata0 channel 0
 atabus1 at ahcisata0 channel 1
 atabus2 at ahcisata0 channel 4
 atabus3 at ahcisata0 channel 5
 ahcisata0 port 0: device present, speed: 3.0Gb/s
 ahcisata0 port 4: device present, speed: 1.5Gb/s
 atapibus0 at atabus2: 1 targets
 cd0 at atapibus0 drive 0: <HL-DT-STDVDRAM GT30N, KZJ9CM31623, 1.01> cdrom 
removable
 cd0: drive supports PIO mode 4, DMA mode 2, Ultra-DMA mode 5 (Ultra/100)
 cd0(ahcisata0:4:0): using PIO mode 4, DMA mode 2, Ultra-DMA mode 5 (Ultra/100) 
(using DMA)
 
 
 Martin