Bug 34882 - Caught 16-bit read from uninitialized memory in elv_set_request
Summary: Caught 16-bit read from uninitialized memory in elv_set_request
Status: RESOLVED UNREPRODUCIBLE
Alias: None
Product: IO/Storage
Classification: Unclassified
Component: Block Layer (show other bugs)
Hardware: All Linux
: P1 normal
Assignee: Jens Axboe
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2011-05-10 19:18 UTC by Christian Casteyde
Modified: 2011-09-01 16:49 UTC (History)
0 users

See Also:
Kernel Version: 2.6.39-rc6
Subsystem:
Regression: Yes
Bisected commit-id:

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Description Christian Casteyde 2011-05-10 19:18:11 UTC 
Acer Aspire 1511LMi
Athlon 64 3GHz in 32 bits mode
512MB
Slackware 13.37
Kernel compiled with kmemcheck + SLUB

Since kernel 2.6.39-rc6 (maybe rc5 but I didn't tested it, I didn't managed to get it before rc4), I get the following warning:

WARNING: kmemcheck: Caught 16-bit read from uninitialized memory (de94ea2c)
0000000053ba74c1000000000000000000000000000000000000000020000000
 i i i i i i i i i i i i u u u u i i i i i i i i i i i i i i i i
                         ^

Pid: 3, comm: ksoftirqd/0 Not tainted 2.6.39-rc6 #6 Acer,Inc. Aspire 1510  /Aspire 1510
EIP: 0060:[<c1219aa5>] EFLAGS: 00010246 CPU: 0
EIP is at cfq_set_request+0x65/0x3a0
EAX: 00000000 EBX: de045a80 ECX: c19873a0 EDX: 00000000
ESI: de012440 EDI: de94ea00 EBP: df491d08 ESP: c188ddcc
 DS: 007b ES: 007b FS: 0000 GS: 00e0 SS: 0068
CR0: 8005003b CR2: deb2c558 CR3: 01886000 CR4: 000006d0
DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
DR6: ffff4ff0 DR7: 00000400
 [<c1207272>] elv_set_request+0x12/0x30
 [<c1209024>] get_request+0x2b4/0x2e0
 [<c120906d>] get_request_wait+0x1d/0x110
 [<c12091b9>] blk_get_request+0x59/0x80
 [<c1369b83>] scsi_execute+0x23/0x120
 [<c1369cff>] scsi_execute_req+0x7f/0x100
 [<c136bcf7>] scsi_probe_and_add_lun+0x1b7/0x920
 [<c136cdbc>] __scsi_add_device+0xec/0x100
 [<c1386a6b>] ata_scsi_scan_host+0xfb/0x180
 [<c1382716>] async_port_probe+0x46/0x70
 [<c104aa5f>] async_run_entry_fn+0x5f/0x150
 [<c103e63b>] process_one_work+0x16b/0x3b0
 [<c103f43a>] worker_thread+0x10a/0x2a0
 [<c104308c>] kthread+0x7c/0x90
 [<c15fbc42>] kernel_thread_helper+0x6/0xd
 [<ffffffff>] 0xffffffff
scsi 0:0:0:0: Direct-Access     ATA      IC25N060ATMR04-0 MO3O PQ: 0 ANSI: 5
sd 0:0:0:0: [sda] 117210240 512-byte logical blocks: (60.0 GB/55.8 GiB)
sd 0:0:0:0: [sda] Write Protect is off
sd 0:0:0:0: [sda] Mode Sense: 00 3a 00 00
sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
sd 0:0:0:0: Attached scsi generic sg0 type 0
tg3 0000:02:06.0: eth0: dma_rwctrl[763f0000] dma_mask[32-bit]
...

It may be the same bug as https://bugzilla.kernel.org/show_bug.cgi?id=33502 but I'm not qualified to tell that.
Comment 1 Christian Casteyde 2011-05-21 08:40:29 UTC 
Update: Still present in 2.6.39.
Comment 2 Christian Casteyde 2011-09-01 16:49:18 UTC 
Update: I cannot reproduce anymore on my new laptop.
The old one is broken, so I cannot test this one anymore.
Closing.
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