On Thu, 17 Sep 2015, Steven Rostedt wrote: > On Thu, 17 Sep 2015 16:38:52 +0200 (CEST) > Thomas Gleixner <t...@linutronix.de> wrote: > > > On Thu, 17 Sep 2015, Steven Rostedt wrote: > > > > > On Thu, 17 Sep 2015 12:13:15 +0200 (CEST) > > > Thomas Gleixner <t...@linutronix.de> wrote: > > > > > > > Digging deeper. My assumption that it's a post powerpc merge failure > > > > turned out to be wrong. > > > > > > Does 4.2 have the problem? > > > > No. Neither does > > > > 4c92b5bb1422: Merge branch 'pcmcia' of > > git://ftp.arm.linux.org.uk/~rmk/linux-arm > > What's the significance of that commit?
It's the commit before the merge of the powerpc tree. ff474e8ca854: Merge tag 'powerpc-4.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux > > It just results in a different failure mode. Instead of silently > > hanging I get: > > > > [ 2.248275] Oops: Exception in kernel mode, sig: 4 [#1] > > [ 2.253633] PREEMPT lite5200 > > [ 2.256584] Modules linked in: > > [ 2.259723] CPU: 0 PID: 1 Comm: swapper Not tainted > > 4.3.0-rc1-51179-gae80a2f-dirty #75 > > [ 2.267815] task: c383c000 ti: c383a000 task.ti: c383a000 > > [ 2.273330] NIP: c00e1eec LR: c00df0f4 CTR: 00000000 > > [ 2.278405] REGS: c383bcd0 TRAP: 0700 Not tainted > > (4.3.0-rc1-51179-gae80a2f-dirty) > > [ 2.286396] MSR: 00089032 <EE,ME,IR,DR,RI> CR: 44824028 XER: 00000000 > > [ 2.293187] > > GPR00: c00def84 c383bd80 c383c000 c3084000 bffffff1 00677595 c383bdd8 > > 00000000 > > GPR08: 00000001 00000001 00000400 00000002 24828022 00000000 c0004254 > > 84822042 > > GPR16: 20000000 44822042 fffff000 c3086ffc c06ce248 c383a000 c3082000 > > c06d0000 > > GPR24: c383a000 00000ffc 00677595 bffffff1 c3084000 c3015bfc 00000017 > > c3086000 > > [ 2.323656] NIP [c00e1eec] vm_normal_page+0x0/0xdc > > [ 2.328560] LR [c00df0f4] follow_page_mask+0x260/0x4fc > > [ 2.333807] Call Trace: > > [ 2.336321] [c383bd80] [c00def84] follow_page_mask+0xf0/0x4fc > > (unreliable) > > [ 2.343360] [c383bdd0] [c00df4a4] __get_user_pages.part.28+0x114/0x3e0 > > [ 2.350050] [c383be30] [c010e788] copy_strings+0x16c/0x2c8 > > [ 2.355668] [c383bea0] [c010e91c] copy_strings_kernel+0x38/0x50 > > [ 2.361730] [c383bec0] [c011057c] do_execveat_common+0x440/0x658 > > [ 2.367877] [c383bf10] [c01107cc] do_execve+0x38/0x48 > > [ 2.373056] [c383bf20] [c00039f0] try_to_run_init_process+0x24/0x64 > > [ 2.379469] [c383bf30] [c000430c] kernel_init+0xb8/0x10c > > [ 2.384924] [c383bf40] [c0010c40] ret_from_kernel_thread+0x5c/0x64 > > [ 2.391242] --- interrupt: 0 at (null) > > [ 2.391242] LR = (null) > > [ 2.398263] Instruction dump: > > [ 2.401297] 01000000 00037000 00000000 00000000 f0000000 00000001 > > 0a641e09 acde4823 > > [ 2.409237] 000f0000 179a7b00 07de2900 03ef1480 <01f78a40> 0001c200 > > 60000000 9421fff0 > > Can you objdump this and and see what that is suppose to be. Certainly not the code at NIP [c00e1eec] vm_normal_page: c00e1eec <vm_normal_page>: c00e1eec: 7c 08 02 a6 mflr r0 c00e1ef0: 90 01 00 04 stw r0,4(r1) c00e1ef4: 4b f2 f6 05 bl c00114f8 <_mcount> c00e1ef8: 94 21 ff f0 stwu r1,-16(r1) c00e1efc: 7c 08 02 a6 mflr r0 c00e1f00: 90 01 00 14 stw r0,20(r1) c00e1f04: 70 a9 08 00 andi. r9,r5,2048 That looks more like random data corruption. > > [ 2.417375] ---[ end trace 996fd312ce9c18ce ]--- > > > > Again, if I disable CONFIG_TRACER its gone. > > You mean if you disable CONFIG_FUNCTION_TRACER? I have to disable both to make it boot. Disabling CONFIG_FUNCTION_TRACER changes the failure mode, but does not make it go away. > Below is the entire push of ftrace for this merge window. Not much has > changed. Could using "unsigned long" instead of "long" with the > MCOUNT_ADDR cause this bug? No, because the trace merge happened after the powerpc merge. But the powerpc merge might be a red herring and the whole issue is caused by something else which just gets unearthed by it. Thanks, tglx _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev