> During exec there is a page fault of 4000b0 but immediately after > that i get another page fault 0f 0x0fc01788 and following register > dump after it > fails to get a fixup address. > > Unable to handle kernel paging request at virtual address > 0fc01788, epc == 00000Oops in fault.c:do_page_fault, line 230: > $0 : 00000000 00000000 00000000 00000000 > $4 : 00007340 800f0474 00000000 801fa000 > $8 : 00000000 00000000 00000000 4c696e75 > $12: 78000000 00000000 00000000 00000000 > $16: 00000000 00000000 00000000 00000000 > $20: 00000000 00000000 00000000 00000000 > $24: 00000000 00000000 > $28: 6e652900 00000000 00000000 00000000 > epc : 00000000 > Status: 00000000 > Cause : 00000000 > Process sh (pid: 1, stackpage=801fa000) > > > i am confused how come the epc status and cause register all are > reported zero. > whether my regs ( pointer to struct pt_regs) is pointing somewhere > else..? When you see a register dump like that, it's a safe bet that your regs pointer is trashed. > secondly Is this a problem with shell or kernel..? may be > somewhere the kernel is not checking the > validity of user space address and hence this problem. By definition, it would be a kernel problem even if the shell *had* made a bogus reference. Worst case, an error in user mode should cause a core dump (of course, if it's init that dumps core, you aren't likely to get to a system login). You seem to be pretty new to this, so let me recommend that you first read the FAQ and related information at http://www.linux-mips.org/, and if you want further help from the mailing list, please specify what CPU and board/system you are targeting, which kernel sources you used, and what tools you used to build it, all of which are pretty important. Kevin K.
