Openmoko Bug #2369: cat s3c2440-uart.1/clock_source causes oops in s3c24xx_serial_show_clksrc

[Openmoko Public Trac]

#2369: cat s3c2440-uart.1/clock_source causes oops in s3c24xx_serial_show_clksrc
--------------------+-------------------------------------------------------
 Reporter:  lindi   |          Owner:  openmoko-kernel
     Type:  defect  |         Status:  new            
 Priority:  normal  |      Milestone:                 
Component:  kernel  |        Version:  unspecified    
 Severity:  normal  |       Keywords:                 
 Haspatch:  0       |      Blockedby:                 
Estimated:          |    Patchreview:                 
 Blocking:          |   Reproducible:  always         
--------------------+-------------------------------------------------------
 Steps to reproduce:
 1) cat /sys/devices/platform/s3c2440-uart.1/clock_source as normal user

 Expected results:
 1) the system does not oops

 Actual results:
 1)

 {{{
 [ 5130.450000] Unable to handle kernel NULL pointer dereference at virtual
 address 00000000
 [ 5130.450000] pgd = c7b7c000
 [ 5130.450000] [00000000] *pgd=36da9031, *pte=00000000, *ppte=00000000
 [ 5130.450000] Internal error: Oops: 17 [#1]
 [ 5130.450000] Modules linked in: ipv6 fuse btusb bluetooth ohci_hcd tun
 snd_soc_neo1973_gta02_wm8753 snd_soc_s3c24xx_i2s snd_soc_s3c24xx g_ether
 snd_soc_wm8753 snd_soc_core snd_pcm_oss snd_mixer_oss ar6000 snd_pcm
 snd_timer snd_page_alloc s3cmci snd s3c2410_wdt
 [ 5130.450000] CPU: 0    Tainted: G        W   (2.6.29-GTA02_lindi2-andy-
 tracking-mokodev #4)
 [ 5130.450000] PC is at s3c24xx_serial_show_clksrc+0x1c/0x30
 [ 5130.450000] LR is at dev_attr_show+0x2c/0x4c
 [ 5130.450000] pc : [<c0189098>]    lr : [<c0189f14>]    psr: a0000013
 [ 5130.450000] sp : c6c8bec8  ip : c6c8bed8  fp : c6c8bed4
 [ 5130.450000] r10: 0001b000  r9 : c6c8a000  r8 : c7b6ac38
 [ 5130.450000] r7 : c037f320  r6 : c78bb5e4  r5 : c7b6ac20  r4 : c037f174
 [ 5130.450000] r3 : 00000000  r2 : c7988000  r1 : 00001000  r0 : c7988000
 [ 5130.450000] Flags: NzCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM
 Segment user
 [ 5130.450000] Control: c000717f  Table: 37b7c000  DAC: 00000015
 [ 5130.450000] Process cat (pid: 8356, stack limit = 0xc6c8a268)
 [ 5130.450000] Stack: (0xc6c8bec8 to 0xc6c8c000)
 [ 5130.450000] bec0:                   c6c8beec c6c8bed8 c0189f14 c018908c
 c036c0f4 c7b6ac20
 [ 5130.450000] bee0: c6c8bf14 c6c8bef0 c00e1a28 c0189ef8 00000000 c6c1e640
 c7b6ac20 c6c8bf78
 [ 5130.450000] bf00: 00008000 c7b6ac38 c6c8bf4c c6c8bf18 c00e1ad4 c00e19b8
 c6c8bf4c c6c8bf28
 [ 5130.450000] bf20: c0034b40 c008d4e0 c6c1e640 0001b000 c6c8bf78 00008000
 c002df48 00000000
 [ 5130.450000] bf40: c6c8bf74 c6c8bf50 c00a10b4 c00e1a8c 00000001 00000000
 00000000 00000000
 [ 5130.450000] bf60: c6c1e640 00000003 c6c8bfa4 c6c8bf78 c00a13d0 c00a100c
 00000000 00000000
 [ 5130.450000] bf80: c0034ee8 00000000 00000000 00008000 0001b000 00000003
 00000000 c6c8bfa8
 [ 5130.450000] bfa0: c002dda0 c00a1394 00008000 0001b000 00000003 0001b000
 00008000 0001b000
 [ 5130.450000] bfc0: 00008000 0001b000 00000003 00000003 0001b000 00000000
 40025000 00000000
 [ 5130.450000] bfe0: 7fffe000 beaef1c0 0000dea0 400eea7c 60000010 00000003
 00000000 00000000
 [ 5130.450000] Backtrace:
 [ 5130.450000] [<c018907c>] (s3c24xx_serial_show_clksrc+0x0/0x30) from
 [<c0189f14>] (dev_attr_show+0x2c/0x4c)
 [ 5130.450000] [<c0189ee8>] (dev_attr_show+0x0/0x4c) from [<c00e1a28>]
 (fill_read_buffer+0x80/0xd4)
 [ 5130.450000]  r5:c7b6ac20 r4:c036c0f4
 [ 5130.450000] [<c00e19a8>] (fill_read_buffer+0x0/0xd4) from [<c00e1ad4>]
 (sysfs_read_file+0x58/0x114)
 [ 5130.450000]  r8:c7b6ac38 r7:00008000 r6:c6c8bf78 r5:c7b6ac20
 r4:c6c1e640
 [ 5130.450000] [<c00e1a7c>] (sysfs_read_file+0x0/0x114) from [<c00a10b4>]
 (vfs_read+0xb8/0x148)
 [ 5130.450000] [<c00a0ffc>] (vfs_read+0x0/0x148) from [<c00a13d0>]
 (sys_read+0x4c/0x7c)
 [ 5130.450000]  r7:00000003 r6:c6c1e640 r5:00000000 r4:00000000
 [ 5130.450000] [<c00a1384>] (sys_read+0x0/0x7c) from [<c002dda0>]
 (ret_fast_syscall+0x0/0x2c)
 [ 5130.450000]  r6:00000003 r5:0001b000 r4:00008000
 [ 5130.450000] Code: e590309c e3a01a01 e513300c e1a00002 (e5933000)
 [ 5130.450000] ---[ end trace ef85096ca71097fb ]---
 }}}

 More info:
 1) this is with andy-tracking 2.6.29 a3587e4ed77974ad

-- 
Ticket URL: <https://docs.openmoko.org/trac/ticket/2369>
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