On Thu, 17 Jan 2008 23:15:27 +0100 Mariusz Kozlowski <[EMAIL PROTECTED]> wrote:
> Hello, > > The script below kills powerpc. oopses get longer and more > wonderful with every next 'cated' file. ppc32. > /proc/<pid>/task/<pid>/pagemap seems to be the cause of oops. The > important thing is that it oopses for random (that is not first in a row) > process from /proc. So not every 'cat /proc/<pid>/task/<pid>/pagemap' > causes an oops. > > I could try to bisect this but this powerpc box is iMac G3 (cpu at 400MHz) > and this will take time. So any hints appreciated. > > Regards, > > Mariusz > > script: > --------- > #!/bin/bash > > for i in `find /proc/*/ -readable -type f`; do > echo -n "cat $i > /dev/null ... "; > logger -t proc_loop $i; > sync; > cat $i > /dev/null; > echo "done"; > done > ---------- > syslog: > proc_loop: /proc/3731/task/3731/pagemap > kernel: BUG: sleeping function called from invalid context at > fs/proc/task_mmu.c:554 > kernel: in_atomic():1, irqs_disabled():0 > kernel: Call Trace: > kernel: [cf1cddf0] [c000840c] show_stack+0x3c/0x194 (unreliable) > kernel: [cf1cde20] [c002b2ec] __might_sleep+0xf4/0x108 > kernel: [cf1cde30] [c00d2d54] add_to_pagemap+0x40/0x11c > kernel: [cf1cde50] [c00d2f44] pagemap_pte_range+0xa8/0x10c > kernel: [cf1cde70] [c0081b30] walk_page_range+0x148/0x23c > kernel: [cf1cdeb0] [c00d3104] pagemap_read+0x15c/0x244 > kernel: [cf1cdef0] [c0092144] vfs_read+0xc4/0x16c > kernel: [cf1cdf10] [c009261c] sys_read+0x4c/0x90 > kernel: [cf1cdf40] [c001328c] ret_from_syscall+0x0/0x40 It's not really an oops - it's a warning. add_to_pagemap() is doing a put_user() inside pagemap_pte_range->pte_offset_map->kmap_atomic. A known bug, I'm afraid. How to fix? - double-buffer the data to be copied to userspace or - take a local copy of the pte page then work on that instead or - play copy_to_user_inatomic() tricks. It would be really nice to get the maps4 stuff merged this time around but it is looking unlikely. > kernel: --- Exception: c01 at 0xff5a364 > kernel: LR = 0x10002f60 > kernel: BUG: scheduling while atomic: cat/8929/0x00000002 > kernel: Call Trace: > kernel: [cf1cde90] [c000840c] show_stack+0x3c/0x194 (unreliable) > kernel: [cf1cdec0] [c002db24] __schedule_bug+0x64/0x78 > kernel: [cf1cdee0] [c027207c] schedule+0x304/0x32c > kernel: [cf1cdf40] [c0013a5c] recheck+0x0/0x28 > kernel: --- Exception: c01 at 0xff5a364 > kernel: LR = 0x10002f60 > kernel: BUG: scheduling while atomic: cat/8929/0x00000007 > kernel: Call Trace: > kernel: [cf1cde90] [c000840c] show_stack+0x3c/0x194 (unreliable) > kernel: [cf1cdec0] [c002db24] __schedule_bug+0x64/0x78 > kernel: [cf1cdee0] [c027207c] schedule+0x304/0x32c > kernel: [cf1cdf40] [c0013a5c] recheck+0x0/0x28 > kernel: --- Exception: c01 at 0xff5a364 > kernel: LR = 0x10002f60 > kernel: BUG: scheduling while atomic: cat/8929/0x00000009 > kernel: Call Trace: > kernel: [cf1cde90] [c000840c] show_stack+0x3c/0x194 (unreliable) > kernel: [cf1cdec0] [c002db24] __schedule_bug+0x64/0x78 > kernel: [cf1cdee0] [c027207c] schedule+0x304/0x32c > kernel: [cf1cdf40] [c0013a5c] recheck+0x0/0x28 > kernel: --- Exception: c01 at 0xff5a364 > kernel: LR = 0x10002f60 > kernel: Page fault in user mode with in_atomic() = 1 mm = cf2765a0 > kernel: NIP = ff0cbc8 MSR = 4000f932 > kernel: Oops: Weird page fault, sig: 11 [#3] hm. Not sure how that happened. The arch code thinks we're running in user mode. > kernel: PREEMPT PowerMac > kernel: Modules linked in: usbhid ide_cd_mod ohci_hcd usbcore uninorth_agp > agpgart > kernel: NIP: 0ff0cbc8 LR: 0ff0d398 CTR: 0ff0d2d0 > kernel: REGS: cf1cdf50 TRAP: 0401 Tainted: G D (2.6.24-rc8-mm1) > kernel: MSR: 4000f932 <EE,PR,FP,ME,IR,DR> CR: 28022442 XER: 00000000 > kernel: TASK = cf8d74f0[8929] 'cat' THREAD: cf1cc000 > kernel: GPR00: 00000001 bf93e330 48029bf0 0ffed488 10016038 28022442 00000000 > 0ff5a364 > kernel: GPR08: 0000f932 00000000 00001032 00000000 28022442 > kernel: NIP [0ff0cbc8] 0xff0cbc8 > kernel: LR [0ff0d398] 0xff0d398 > proc_loop: /proc/3731/task/3731/wchan > kernel: Call Trace: > kernel: ---[ end trace 54bd1ed4883922c9 ]--- > kernel: note: cat[8929] exited with preempt_count 10 > proc_loop: /proc/3731/task/3731/oom_score > proc_loop: /proc/3731/task/3731/oom_adj > proc_loop: /proc/3731/fdinfo/0 > [... snip ...] _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
