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Date: Wed, 20 Aug 2008 00:10:14 +0200 From: Dmitry Adamushko <dmitry.adamushko@...il.com> To: Ingo Molnar <mingo@...e.hu> Cc: Peter Oruba <peter.oruba@....com>, Tigran Aivazian <tigran@...azian.fsnet.co.uk>, Max Krasnyansky <maxk@...lcomm.com>, Peter Zijlstra <a.p.zijlstra@...llo.nl>, LKML <linux-kernel@...r.kernel.org> Subject: [0/2 -tip] microcode: bug-fix + updates [ Peter Z., you may jump immediately to [*] :-) ] [1/2] [-tip, BUG-fix] microcode: fix unbalanced use of get_cpu() check a boot-up CPU (#0) in microcode_{intel,amd}_module_init(). [2/2] [-tip] microcode: refactoring This is the 1st patch is series. Here the aim was to avoid any significant changes, logically-wise. So it's mainly about generic interface refactoring: e.g. make microcode_{intel,amd}.c more about arch-specific details and less about policies like make-sure-we-run-on-a-target-cpu (no more set_cpus_allowed_ptr() here) and generic synchronization (no more microcode_mutex here). All in all, more line have been deleted than added. 4 files changed, 145 insertions(+), 198 deletions(-) Note, I've only done some basic testing. Someone with ucode firmware files is very welcome to give this code a try. [*] btw., with DEBUG being enabled, pr_debug() generates [1] when debug_smp_processor_id() is used (CONFIG_DEBUG_PREEMPT). the problem seems to be caused by the following commit: commit b845b517b5e3706a3729f6ea83b88ab85f0725b0 Author: Peter Zijlstra <a.p.zijlstra@...llo.nl> Date: Fri Aug 8 21:47:09 2008 +0200 printk: robustify printk wake_up_klogd() -> __get_cpu_var() -> smp_processor_id() and that's being called from release_console_sem() which is, in turn, said to be "may be called from any context" [2] and in this case, it seems to be called from some non-preemptible context (although, it can't be printk()... although, I haven't looked carefully yet). Provided [2], __get_cpu_var() is perhaps not the right solution there. [1] [ 7697.942005] BUG: using smp_processor_id() in preemptible [00000000] code: syslogd/3542 [ 7697.942005] caller is wake_up_klogd+0x1b/0x50 [ 7697.942005] Pid: 3542, comm: syslogd Not tainted 2.6.27-rc3-tip-git #2 [ 7697.942005] Call Trace: [ 7697.942005] [<ffffffff8036b398>] debug_smp_processor_id+0xe8/0xf0 [ 7697.942005] [<ffffffff80239d3b>] wake_up_klogd+0x1b/0x50 [ 7697.942005] [<ffffffff8023a047>] release_console_sem+0x1e7/0x200 [ 7697.942005] [<ffffffff803c0f17>] do_con_write+0xb7/0x1f30 [ 7697.942005] [<ffffffff8020d920>] ? show_trace+0x10/0x20 [ 7697.942005] [<ffffffff8020dc42>] ? dump_stack+0x72/0x80 [ 7697.942005] [<ffffffff8036392d>] ? __ratelimit+0xbd/0xe0 [ 7697.942005] [<ffffffff8036b398>] ? debug_smp_processor_id+0xe8/0xf0 [ 7697.942005] [<ffffffff80239d3b>] ? wake_up_klogd+0x1b/0x50 [ 7697.942005] [<ffffffff8023a047>] ? release_console_sem+0x1e7/0x200 [ 7697.942005] [<ffffffff803c2de9>] con_write+0x19/0x30 [ 7697.942005] [<ffffffff803b37b6>] write_chan+0x276/0x3c0 [ 7697.942005] [<ffffffff80232b20>] ? default_wake_function+0x0/0x10 [ 7697.942005] [<ffffffff804cb872>] ? _spin_lock_irqsave+0x22/0x50 [ 7697.942005] [<ffffffff803b1334>] tty_write+0x194/0x260 [ 7697.942005] [<ffffffff803b3540>] ? write_chan+0x0/0x3c0 [ 7697.942005] [<ffffffff803b14a4>] redirected_tty_write+0xa4/0xb0 [ 7697.942005] [<ffffffff803b1400>] ? redirected_tty_write+0x0/0xb0 [ 7697.942005] [<ffffffff802a88c2>] do_loop_readv_writev+0x52/0x80 [ 7697.942005] [<ffffffff802a939d>] do_readv_writev+0x1bd/0x1d0 [ 7697.942005] [<ffffffff802a93e9>] vfs_writev+0x39/0x60 [ 7697.942005] [<ffffffff802a9870>] sys_writev+0x50/0x90 [ 7697.942005] [<ffffffff8020bb3b>] system_call_fastpath+0x16/0x1b --Dmitry -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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