From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757178AbYBKW3O (ORCPT ); Mon, 11 Feb 2008 17:29:14 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753879AbYBKW27 (ORCPT ); Mon, 11 Feb 2008 17:28:59 -0500 Received: from e35.co.us.ibm.com ([32.97.110.153]:52031 "EHLO e35.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753814AbYBKW26 (ORCPT ); Mon, 11 Feb 2008 17:28:58 -0500 Date: Mon, 11 Feb 2008 14:28:55 -0800 From: Nishanth Aravamudan To: Andrew Morton Cc: Miles Lane , LKML , Adam Litke , David Gibson Subject: Re: 2.6.24-git20 -- BUG: sleeping function called from invalid context at include/asm/uaccess_32.h:449 Message-ID: <20080211222855.GA9138@us.ibm.com> References: <20080209162643.fd3822f1.akpm@linux-foundation.org> <20080210212528.GA17442@us.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080210212528.GA17442@us.ibm.com> X-Operating-System: Linux 2.6.24-7-generic (i686) User-Agent: Mutt/1.5.17+20080114 (2008-01-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10.02.2008 [13:25:28 -0800], Nishanth Aravamudan wrote: > On 09.02.2008 [16:26:43 -0800], Andrew Morton wrote: > > On Sat, 9 Feb 2008 14:03:28 -0500 "Miles Lane" wrote: > > > > > Command run: > > > find /proc | xargs tail > > > > > > [ 2710.028219] BUG: sleeping function called from invalid context at > > > include/asm/uaccess_32.h:449 > > > [ 2710.028229] in_atomic():1, irqs_disabled():0 > > > [ 2710.028232] 1 lock held by head/9380: > > > [ 2710.028234] #0: (hugetlb_lock){--..}, at: [] > > > hugetlb_overcommit_handler+0x16/0x3e > > > [ 2710.028248] Pid: 9380, comm: head Not tainted 2.6.24-git20 #5 > > > [ 2710.028260] [] __might_sleep+0xc2/0xc9 > > > [ 2710.028267] [] copy_to_user+0x32/0x49 > > > [ 2710.028277] [] do_proc_doulongvec_minmax+0x1df/0x27f > > > [ 2710.028289] [] proc_doulongvec_minmax+0x15/0x17 > > > [ 2710.028295] [] hugetlb_overcommit_handler+0x2a/0x3e > > > [ 2710.028303] [] proc_sys_read+0x5e/0x7b > > > [ 2710.028311] [] ? proc_sys_read+0x0/0x7b > > > [ 2710.028317] [] vfs_read+0x8a/0x106 > > > [ 2710.028325] [] sys_read+0x3b/0x60 > > > [ 2710.028331] [] sysenter_past_esp+0x5f/0xa5 > > > > Ugh, how did I let that one through? > > Don't blame yourself, blame me. > > > Guys, how often mut it be said? > > Hopefully this is often enough. > > > PLEASE always test all code with all kernel deubg options enabled. > > Yep, 100% my error. Am testing a fix now, will post soon. While I'm not removing the brown paper bag from my head, I was unable to reproduce the BUG on my 2-way x86_64 at home. I then noticed Miles' system is x86_32. After wrangling with our testing grid, I got a 32-bit system booting 2.6.24-git22. Didn't reproduce there either, with CONFIG_DEBUG_SPINLOCK_SLEEP=y. What am I doing wrong? I think the following is the right fix, but have not see the original BUG to know for sure. I did the `find /proc | xargs tail`, but shouldn't I hit the BUG just simply `cat`'ing or `echo`ing into the file? Miles, could you test the following? Thanks, Nish hugetlb: fix overcommit locking proc_doulongvec_minmax() calls copy_to_user()/copy_from_user(), so we can't hold hugetlb_lock over the call. Use a dummy variable to store the sysctl result, like in hugetlb_sysctl_handler(), then grab the lock to update nr_overcommit_huge_pages. Signed-off-by: Nishanth Aravamudan diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index 7ca198b..addca4c 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -33,8 +33,8 @@ int hugetlb_reserve_pages(struct inode *inode, long from, long to); void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed); extern unsigned long max_huge_pages; +extern unsigned long sysctl_overcommit_huge_pages; extern unsigned long hugepages_treat_as_movable; -extern unsigned long nr_overcommit_huge_pages; extern const unsigned long hugetlb_zero, hugetlb_infinity; extern int sysctl_hugetlb_shm_group; diff --git a/kernel/sysctl.c b/kernel/sysctl.c index d41ef6b..2024632 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -978,8 +978,8 @@ static struct ctl_table vm_table[] = { { .ctl_name = CTL_UNNUMBERED, .procname = "nr_overcommit_hugepages", - .data = &nr_overcommit_huge_pages, - .maxlen = sizeof(nr_overcommit_huge_pages), + .data = &sysctl_overcommit_huge_pages, + .maxlen = sizeof(sysctl_overcommit_huge_pages), .mode = 0644, .proc_handler = &hugetlb_overcommit_handler, }, diff --git a/mm/hugetlb.c b/mm/hugetlb.c index d9a3803..cb1b3a7 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -24,14 +24,15 @@ const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL; static unsigned long nr_huge_pages, free_huge_pages, resv_huge_pages; static unsigned long surplus_huge_pages; +static unsigned long nr_overcommit_huge_pages; unsigned long max_huge_pages; +unsigned long sysctl_overcommit_huge_pages; static struct list_head hugepage_freelists[MAX_NUMNODES]; static unsigned int nr_huge_pages_node[MAX_NUMNODES]; static unsigned int free_huge_pages_node[MAX_NUMNODES]; static unsigned int surplus_huge_pages_node[MAX_NUMNODES]; static gfp_t htlb_alloc_mask = GFP_HIGHUSER; unsigned long hugepages_treat_as_movable; -unsigned long nr_overcommit_huge_pages; static int hugetlb_next_nid; /* @@ -609,8 +610,9 @@ int hugetlb_overcommit_handler(struct ctl_table *table, int write, struct file *file, void __user *buffer, size_t *length, loff_t *ppos) { - spin_lock(&hugetlb_lock); proc_doulongvec_minmax(table, write, file, buffer, length, ppos); + spin_lock(&hugetlb_lock); + nr_overcommit_huge_pages = sysctl_overcommit_huge_pages; spin_unlock(&hugetlb_lock); return 0; }