On Mon, Oct 21, 2013 at 9:34 AM, Michael Schmitz
<schmitz@xxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
this looks like it might be related to the ESP driver - scsi_finish_command
called from the swapper process during apt-get dist-upgrade does seem
plausible.
Some of the Amiga SCSI drivers did fiddle with the chip interrupt enable on
SCSI interrupt entry, but I'd have thought the ESP core is reasonably
thread-safe these days.
To pinpoint where in sd_completed_bytes this happens, I'd need the sd_mod
module and the module symbol map.
/* be careful ... don't want any overflows */
u64 factor = scmd->device->sector_size / 512;
do_div(start_lba, factor);
do_div(end_lba, factor);
scmd->device->sector_size should be 512, so factor should be 1.
Let's try a bit harder with a fresher mind and a cup of coffee and
a mini-twix:
[77568.320000] PC: [<0484c33a>] sd_completed_bytes+0x90/0xe8 [sd_mod]
[77568.330000] SR: 2000 SP: 00277e58 a2: 0027e2e4
[77568.340000] d0: 00000000 d1: 007735a0 d2: 00000000 d3: 00000001
[77568.350000] d4: 00000000 d5: 007735a8 a0: 024dd000 a1: 024a0ea0
[77569.190000] Code: 4a80 6704 4c42 0001 2c01 2207 4c42 1406 <2c00> 2e01
2004 2204 6704 4c42 0001 2801 2205 4c42 1404 2800 2a01 202e fff8 222e
"4c42" is a division. It's the second one of the four divisions:
0: 4a80 tstl %d0
d0 is zero, so the first division is skipped.
2: 6704 beqs 0x8
4: 4c42 0001 divull %d2,%d1,%d0
8: 2c01 movel %d1,%d6
a: 2207 movel %d7,%d1
c: 4c42 1406 divul %d2,%d6,%d1
It's dividing by d2, which is zero. So scmd->device->sector_size must be
smaller than 512 (probably zero).
10: 2c00 movel %d0,%d6
12: 2e01 movel %d1,%d7
14: 2004 movel %d4,%d0
16: 2204 movel %d4,%d1
18: 6704 beqs 0x1e
1a: 4c42 0001 divull %d2,%d1,%d0
1e: 2801 movel %d1,%d4
20: 2205 movel %d5,%d1
22: 4c42 1404 divul %d2,%d4,%d1
26: 2800 movel %d0,%d4
28: 2a01 movel %d1,%d5
2a: 202e fff8 movel %fp@(-8),%d0
The posted binary has slightly different code (different addresses, and the
division is "4c40"):
00168404 <sd_completed_bytes>:
168404: 4e56 fff8 linkw %fp,#-8
168408: 48e7 3f1c moveml %d2-%d7/%a3-%a5,%sp@-
16840c: 266e 0008 moveal %fp@(8),%a3
168410: 206b 0054 moveal %a3@(84),%a0
168414: 2828 0032 movel %a0@(50),%d4
168418: 2a28 0036 movel %a0@(54),%d5
16841c: 2c2b 0040 movel %a3@(64),%d6
168420: 2e2b 0044 movel %a3@(68),%d7
168424: 7001 moveq #1,%d0
168426: b0a8 0022 cmpl %a0@(34),%d0
16842a: 6600 00b2 bnew 1684de <sd_completed_bytes+0xda>
16842e: 486e fff8 pea %fp@(-8)
168432: 4878 0060 pea 60 <PAGE_TABLE_SIZE+0x20>
168436: 2f2b 0058 movel %a3@(88),%sp@-
16843a: 4eb9 0015 4e86 jsr 154e86 <scsi_get_sense_info_fld>
168440: 4fef 000c lea %sp@(12),%sp
168444: 4a80 tstl %d0
168446: 6700 0096 beqw 1684de <sd_completed_bytes+0xda>
16844a: 2053 moveal %a3@,%a0
16844c: 2028 0054 movel %a0@(84),%d0
168450: b0ab 0040 cmpl %a3@(64),%d0
168454: 6400 0088 bccw 1684de <sd_completed_bytes+0xda>
168458: 2206 movel %d6,%d1
16845a: 7409 moveq #9,%d2
16845c: e4a9 lsrl %d2,%d1
16845e: 2601 movel %d1,%d3
168460: 4202 clrb %d2
168462: d685 addl %d5,%d3
168464: d584 addxl %d4,%d2
168466: 0c80 0000 01ff cmpil #511,%d0
16846c: 6212 bhis 168480 <sd_completed_bytes+0x7c>
16846e: da85 addl %d5,%d5
168470: d984 addxl %d4,%d4
168472: 2002 movel %d2,%d0
168474: 2203 movel %d3,%d1
168476: d281 addl %d1,%d1
168478: d180 addxl %d0,%d0
16847a: 2840 moveal %d0,%a4
16847c: 2a41 moveal %d1,%a5
16847e: 602a bras 1684aa <sd_completed_bytes+0xa6>
168480: 7209 moveq #9,%d1
168482: e2a8 lsrl %d1,%d0
168484: 2204 movel %d4,%d1
168486: 2045 moveal %d5,%a0
168488: 6704 beqs 16848e <sd_completed_bytes+0x8a>
16848a: 4c40 1004 divull %d0,%d4,%d1
16848e: 2a08 movel %a0,%d5
168490: 4c40 5404 divul %d0,%d4,%d5
168494: 2801 movel %d1,%d4
168496: 2202 movel %d2,%d1
168498: 2043 moveal %d3,%a0
16849a: 6704 beqs 1684a0 <sd_completed_bytes+0x9c>
16849c: 4c40 1002 divull %d0,%d2,%d1
1684a0: 2608 movel %a0,%d3
1684a2: 4c40 3402 divul %d0,%d2,%d3
1684a6: 2841 moveal %d1,%a4
1684a8: 2a43 moveal %d3,%a5
1684aa: 202e fff8 movel %fp@(-8),%d0
1684ae: 222e fffc movel %fp@(-4),%d1
1684b2: 2400 movel %d0,%d2
1684b4: 2601 movel %d1,%d3
1684b6: 9685 subl %d5,%d3
1684b8: 9584 subxl %d4,%d2
1684ba: 6522 bcss 1684de <sd_completed_bytes+0xda>
1684bc: 240c movel %a4,%d2
1684be: 260d movel %a5,%d3
1684c0: 9681 subl %d1,%d3
1684c2: 9580 subxl %d0,%d2
1684c4: 6318 blss 1684de <sd_completed_bytes+0xda>
1684c6: 9285 subl %d5,%d1
1684c8: 9184 subxl %d4,%d0
1684ca: 2053 moveal %a3@,%a0
1684cc: 9c87 subl %d7,%d6
1684ce: 2028 0054 movel %a0@(84),%d0
1684d2: 4c01 0800 mulsl %d1,%d0
1684d6: bc80 cmpl %d0,%d6
1684d8: 6406 bccs 1684e0 <sd_completed_bytes+0xdc>
1684da: 2006 movel %d6,%d0
1684dc: 6002 bras 1684e0 <sd_completed_bytes+0xdc>
1684de: 4280 clrl %d0
1684e0: 4cee 38fc ffd4 moveml %fp@(-44),%d2-%d7/%a3-%a5
1684e6: 4e5e unlk %fp
1684e8: 4e75 rts
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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