> When I try a cat /dev/ram0 , the cursor will blink like it is working and I > can see that the kernel hasn't crashed. Eventually, it fails as well, but > on a null virtual address. I have the output below and have cut it short so > as to not include too much. Can someone tell me if this is normal and if it > isn't, what could be the cause of it (setup issue with kernel etc). I am > running 2.6.20, with the AT91 patches. /dev/ram0 is a ramdisk, usually not very useful because it only contains a small part of the memory. > # cat /dev/ram0 Uhm, try cat /dev/ram0 > /dev/null Without the redirect cat will spew the contents on the tty which can really upset your terminal emulator and shell. Erik - I did use devmem2 and can access memory locations on the arm. The issue for me, it seems, is like the arm doesn't know what the boundaries are or that they are not setup properly. In effect, it *seems* like it thinks there are 10 locations, lets say, and something is setup to only have 8, and when it accesses the 9th, it's bogus. I wasn't too worried about it throwing up stuff to the terminal when I tried the original. I just wanted to see if it wouldn't crash. So, you're suggestion was also good and yes, it crashes at the same spot. I'll include the output below. The reason I picked on this is because it is crashing in the same way that other programs have been crashing on me so I thought it may be a good and easy thing that if I can get this to work, the others should as well. Anything else I could try to see if things are setup correctly? # cat /dev/ram0 > /dev/null [ 1194.070000] Unable to handle kernel NULL pointer dereference at virtual addre ss 00000000 [ 1194.070000] pgd = c1f94000 [ 1194.070000] [00000000] *pgd=21f73031, *pte=00000000, *ppte=00000000 [ 1194.070000] Internal error: Oops: 17 [#1] [ 1194.070000] Modules linked in: [ 1194.070000] CPU: 0 [ 1194.070000] PC is at __wake_up_common+0x30/0xbc [ 1194.070000] LR is at __wake_up+0x40/0x6c [ 1194.070000] pc : [<c003f460>] lr : [<c00404e4>] Not tainted [ 1194.070000] sp : c1f77cf0 ip : c1f77d20 fp : c1f77d1c [ 1194.070000] r10: 00000003 r9 : c1f77d40 r8 : 00000000 [ 1194.070000] r7 : 00000001 r6 : c0000070 r5 : a0000013 r4 : c1f76000 [ 1194.070000] r3 : 00000000 r2 : 00000001 r1 : fffffff4 r0 : 00000000 [ 1194.070000] Flags: nzcv IRQs off FIQs on Mode SVC_32 Segment user [ 1194.070000] Control: C000717F [ 1194.070000] Table: 21F94000 DAC: 00000015 [ 1194.070000] Process cat (pid: 258, stack limit = 0xc1f76258) [ 1194.070000] Stack: (0xc1f77cf0 to 0xc1f78000) [ 1194.070000] 7ce0: 0000002c c1f76000 a0000 013 c0335144 [ 1194.070000] 7d00: 00000079 00000000 00001000 00000000 c1f77d3c c1f77d20 c0040 4e4 c003f440 [ 1194.070000] 7d20: c1f77d40 c0335144 c030d000 c030d000 c1f77d54 c1f77d40 c005c 528 c00404b4 [ 1194.070000] 7d40: c030d000 00000000 c1f77d6c c1f77d58 c006c23c c005c508 c030d 000 c030d000 [ 1194.070000] 7d60: c1f77d84 c1f77d70 c0174db8 c006c204 00000000 00000000 c1f77 e24 c1f77d88 [ 1194.070000] 7d80: c006cc68 c0174d9c 00000001 00000000 00079000 00000000 c0071 1e8 c1f77dd0 [ 1194.070000] 7da0: c1f77ed8 c1e86f54 c1e86f98 c03350ac 000003ff 0000007a 00000 07a 00000078 [ 1194.070000] 7dc0: 00400000 00000000 00000000 c1f76000 00000000 00000000 00000 001 00000000 [ 1194.070000] 7de0: 00000079 00000000 00000000 00000000 00000000 00000000 00000 001 c1f77f18 [ 1194.070000] 7e00: 00000001 00000000 00000001 c1e86f54 c1f77f18 00000000 c1f77 e7c c1f77e28 [ 1194.070000] 7e20: c006f6b0 c006cac8 c1f77e40 c006bf50 c01385d0 c0137f80 00000 032 c1f77ed8 [ 1194.070000] 7e40: 00000000 00001000 bed7dd00 00000000 c1f76000 c1f77e88 c1f77 f18 c1e86f54 [ 1194.070000] 7e60: fffffdee c1f77f78 c1f76000 00900003 c1f77f44 c1f77e80 c008c 2dc c006f5a8 [ 1194.070000] 7e80: 00079000 00000000 00000020 00000000 00000000 00000001 fffff fff c1e86f54 [ 1194.070000] 7ea0: 00000000 00000000 00000000 00000000 c037bd60 00000000 00000 000 00000000 [ 1194.070000] 7ec0: c1f77f34 c037bd60 c005c558 c1f77ecc c1f77ecc c02b2fdc 00079 000 00000000 [ 1194.070000] 7ee0: bed7dcec 00000000 c1e682c0 c002acc8 c1f95000 00001000 00000 000 c0033e6c [ 1194.070000] 7f00: c1f14000 00000002 c1f77f3c 00000000 00000000 c1e682c0 bed7d d00 00001000 [ 1194.070000] 7f20: c1d14a24 c1e86f54 bed7dd00 c1f77f78 00001000 c1f76000 c1f77 f74 c1f77f48 [ 1194.070000] 7f40: c008cd4c c008c220 00000000 40059000 00000004 c1e86f54 00079 000 00000000 [ 1194.070000] 7f60: 00000003 c002d604 c1f77fa4 c1f77f78 c008d2b4 c008cca0 00079 000 00000000 [ 1194.070000] 7f80: 00000005 00000000 bed7dd00 00001000 bed7dd00 4008b390 00000 000 c1f77fa8 [ 1194.070000] 7fa0: c002ce20 c008d278 00001000 bed7dd00 00000004 bed7dd00 00001 000 000a6cfc [ 1194.070000] 7fc0: 00001000 bed7dd00 4008b390 00000004 00000001 00000002 00000 004 0000d2fc [ 1194.070000] 7fe0: 000a6a2c bed7dce4 0003a74c 40058c1c 60000010 00000004 20002 031 20002431 [ 1194.070000] Backtrace: [ 1194.070000] [<c003f430>] (__wake_up_common+0x0/0xbc) from [<c00404e4>] (__wak e_up+0x40/0x6c) [ 1194.070000] [<c00404a4>] (__wake_up+0x0/0x6c) from [<c005c528>] (__wake_up_bi t+0x30/0x38) [ 1194.070000] r5 = C030D000 r4 = C030D000 [ 1194.070000] [<c005c4f8>] (__wake_up_bit+0x0/0x38) from [<c006c23c>] (unlock_p age+0x48/0x4c) [ 1194.070000] [<c006c1f4>] (unlock_page+0x0/0x4c) from [<c0174db8>] (ramdisk_re adpage+0x2c/0x34) [ 1194.070000] r4 = C030D000 [ 1194.070000] [<c0174d8c>] (ramdisk_readpage+0x0/0x34) from [<c006cc68>] (do_ge neric_mapping_read+0x1b0/0x5dc) [ 1194.070000] r4 = 00000000 [ 1194.070000] [<c006cab8>] (do_generic_mapping_read+0x0/0x5dc) from [<c006f6b0> ] (generic_file_aio_read+0x118/0x228) [ 1194.070000] [<c006f598>] (generic_file_aio_read+0x0/0x228) from [<c008c2dc>] (do_sync_read+0xcc/0x118) [ 1194.070000] [<c008c210>] (do_sync_read+0x0/0x118) from [<c008cd4c>] (vfs_read +0xbc/0x19c) [ 1194.070000] r8 = C1F76000 r7 = 00001000 r6 = C1F77F78 r5 = BED7DD00 [ 1194.070000] r4 = C1E86F54 [ 1194.070000] [<c008cc90>] (vfs_read+0x0/0x19c) from [<c008d2b4>] (sys_read+0x4 c/0x84) [ 1194.070000] r8 = C002D604 r7 = 00000003 r6 = 00000000 r5 = 00079000 [ 1194.070000] r4 = C1E86F54 [ 1194.070000] [<c008d268>] (sys_read+0x0/0x84) from [<c002ce20>] (ret_fast_sysc all+0x0/0x2c) [ 1194.070000] r6 = 4008B390 r5 = BED7DD00 r4 = 00001000 [ 1194.070000] Code: e240100c e1a08003 e1a07002 e59b9004 (e591300c) [ 1194.760000] <6>note: cat[258] exited with preempt_count 1 [ 1194.770000] BUG: scheduling while atomic: cat/0x40000001/258 [ 1194.770000] [<c0031b48>] (dump_stack+0x0/0x14) from [<c022c938>] (schedule+0x 7f8/0x85c) [ 1194.780000] [<c022c140>] (schedule+0x0/0x85c) from [<c003f584>] (__cond_resch ed+0x28/0x44) [ 1194.790000] [<c003f55c>] (__cond_resched+0x0/0x44) from [<c022d488>] (cond_re sched+0x48/0x54) [ 1194.800000] r4 = 00000001 [ 1194.800000] [<c022d440>] (cond_resched+0x0/0x54) from [<c007a7c0>] (unmap_vma s+0x634/0x65c) [ 1194.810000] r4 = C1F738E0 [ 1194.810000] [<c007a18c>] (unmap_vmas+0x0/0x65c) from [<c007dbac>] (exit_mmap+ 0x7c/0x154) [ 1194.820000] [<c007db30>] (exit_mmap+0x0/0x154) from [<c0041d40>] (mmput+0x44/ 0xe0) [ 1194.830000] [<c0041cfc>] (mmput+0x0/0xe0) from [<c0046040>] (exit_mm+0xac/0x1 04) [ 1194.840000] r4 = C1F76000 [ 1194.840000] [<c0045f94>] (exit_mm+0x0/0x104) from [<c00479e4>] (do_exit+0x124 /0x948) [ 1194.850000] r7 = 00000001 r6 = C1F78000 r5 = C037BD60 r4 = C1F77D1C [ 1194.850000] [<c00478c0>] (do_exit+0x0/0x948) from [<c0031a4c>] (die+0x2b8/0x2 fc) [ 1194.860000] [<c0031794>] (die+0x0/0x2fc) from [<c0033e4c>] (__do_kernel_fault +0x6c/0x7c) [ 1194.870000] [<c0033de0>] (__do_kernel_fault+0x0/0x7c) from [<c0033f8c>] (do_p age_fault+0x130/0x24c) [ 1194.880000] r7 = 00000000 r6 = C02B304C r5 = C002ACC8 r4 = C037BD60 [ 1194.880000] [<c0033e5c>] (do_page_fault+0x0/0x24c) from [<c0034218>] (do_Data Abort+0x3c/0xa0) [ 1194.890000] [<c00341dc>] (do_DataAbort+0x0/0xa0) from [<c002c9e0>] (__dabt_sv c+0x40/0x60) [ 1194.900000] r8 = 00000000 r7 = 00000001 r6 = C0000070 r5 = C1F77CDC [ 1194.910000] r4 = FFFFFFFF [ 1194.910000] [<c003f430>] (__wake_up_common+0x0/0xbc) from [<c00404e4>] (__wak e_up+0x40/0x6c) [ 1194.920000] [<c00404a4>] (__wake_up+0x0/0x6c) from [<c005c528>] (__wake_up_bi t+0x30/0x38) [ 1194.930000] r5 = C030D000 r4 = C030D000 [ 1194.930000] [<c005c4f8>] (__wake_up_bit+0x0/0x38) from [<c006c23c>] (unlock_p age+0x48/0x4c) [ 1194.940000] [<c006c1f4>] (unlock_page+0x0/0x4c) from [<c0174db8>] (ramdisk_re adpage+0x2c/0x34) [ 1194.950000] r4 = C030D000 [ 1194.950000] [<c0174d8c>] (ramdisk_readpage+0x0/0x34) from [<c006cc68>] (do_ge neric_mapping_read+0x1b0/0x5dc) [ 1194.960000] r4 = 00000000 [ 1194.970000] [<c006cab8>] (do_generic_mapping_read+0x0/0x5dc) from [<c006f6b0> ] (generic_file_aio_read+0x118/0x228) [ 1194.980000] [<c006f598>] (generic_file_aio_read+0x0/0x228) from [<c008c2dc>] (do_sync_read+0xcc/0x118) [ 1194.980000] [<c008c210>] (do_sync_read+0x0/0x118) from [<c008cd4c>] (vfs_read +0xbc/0x19c) [ 1194.990000] r8 = C1F76000 r7 = 00001000 r6 = C1F77F78 r5 = BED7DD00 [ 1195.000000] r4 = C1E86F54 [ 1195.000000] [<c008cc90>] (vfs_read+0x0/0x19c) from [<c008d2b4>] (sys_read+0x4 c/0x84) [ 1195.010000] r8 = C002D604 r7 = 00000003 r6 = 00000000 r5 = 00079000 [ 1195.020000] r4 = C1E86F54 [ 1195.020000] [<c008d268>] (sys_read+0x0/0x84) from [<c002ce20>] (ret_fast_sysc all+0x0/0x2c) [ 1195.030000] r6 = 4008B390 r5 = BED7DD00 r4 = 00001000 -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ 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