From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f199.google.com (mail-pf0-f199.google.com [209.85.192.199]) by kanga.kvack.org (Postfix) with ESMTP id 568666B0333 for ; Fri, 24 Mar 2017 06:55:26 -0400 (EDT) Received: by mail-pf0-f199.google.com with SMTP id o126so20948549pfb.2 for ; Fri, 24 Mar 2017 03:55:26 -0700 (PDT) Received: from www262.sakura.ne.jp (www262.sakura.ne.jp. [2001:e42:101:1:202:181:97:72]) by mx.google.com with ESMTPS id f67si1647523pff.317.2017.03.24.03.55.22 for (version=TLS1 cipher=AES128-SHA bits=128/128); Fri, 24 Mar 2017 03:55:22 -0700 (PDT) From: Tetsuo Handa Subject: [PATCH] mm: Remove pointless might_sleep() in remove_vm_area(). Date: Fri, 24 Mar 2017 19:53:28 +0900 Message-Id: <1490352808-7187-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp> Sender: owner-linux-mm@kvack.org List-ID: To: linux-mm@kvack.org Cc: Tetsuo Handa , Matthew Wilcox , Christoph Hellwig , Jisheng Zhang , Andrey Ryabinin , Joel Fernandes , Chris Wilson , John Dias , Thomas Gleixner , "H. Peter Anvin" , Ingo Molnar Commit 5803ed292e63a1bf ("mm: mark all calls into the vmalloc subsystem as potentially sleeping") added might_sleep() to remove_vm_area() from vfree(), and is causing [ 2.616064] BUG: sleeping function called from invalid context at mm/vmalloc.c:1480 [ 2.616125] in_atomic(): 1, irqs_disabled(): 0, pid: 341, name: plymouthd [ 2.616156] 2 locks held by plymouthd/341: [ 2.616158] #0: (drm_global_mutex){+.+.+.}, at: [] drm_release+0x3b/0x3b0 [drm] [ 2.616256] #1: (&(&tfile->lock)->rlock){+.+...}, at: [] ttm_object_file_release+0x28/0x90 [ttm] [ 2.616270] CPU: 2 PID: 341 Comm: plymouthd Not tainted 4.11.0-0.rc3.git0.1.kmallocwd.fc25.x86_64+debug #1 [ 2.616271] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 07/02/2015 [ 2.616273] Call Trace: [ 2.616281] dump_stack+0x86/0xc3 [ 2.616285] ___might_sleep+0x17d/0x250 [ 2.616289] __might_sleep+0x4a/0x80 [ 2.616293] remove_vm_area+0x22/0x90 [ 2.616296] __vunmap+0x2e/0x110 [ 2.616299] vfree+0x42/0x90 [ 2.616304] kvfree+0x2c/0x40 [ 2.616312] drm_ht_remove+0x1a/0x30 [drm] [ 2.616317] ttm_object_file_release+0x50/0x90 [ttm] [ 2.616324] vmw_postclose+0x47/0x60 [vmwgfx] [ 2.616331] drm_release+0x290/0x3b0 [drm] [ 2.616338] __fput+0xf8/0x210 [ 2.616342] ____fput+0xe/0x10 [ 2.616345] task_work_run+0x85/0xc0 [ 2.616351] exit_to_usermode_loop+0xb4/0xc0 [ 2.616355] do_syscall_64+0x185/0x1f0 [ 2.616359] entry_SYSCALL64_slow_path+0x25/0x25 warning. But commit f9e09977671b618a ("mm: turn vmap_purge_lock into a mutex") did not make vfree() potentially sleeping because try_purge_vmap_area_lazy() is still using mutex_trylock(). Thus, this is a false positive warning. ___might_sleep() via cond_resched_lock() in __purge_vmap_area_lazy() from try_purge_vmap_area_lazy() from free_vmap_area_noflush() from free_unmap_vmap_area() from remove_vm_area() which might trigger same false positive warning is remaining. But so far we haven't heard about warning from that path. Signed-off-by: Tetsuo Handa Cc: Matthew Wilcox Cc: Christoph Hellwig Cc: Jisheng Zhang Cc: Andrey Ryabinin Cc: Joel Fernandes Cc: Chris Wilson Cc: John Dias Cc: Thomas Gleixner Cc: "H. Peter Anvin" Cc: Ingo Molnar --- mm/vmalloc.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 68eb002..32be3c4 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -1477,8 +1477,6 @@ struct vm_struct *remove_vm_area(const void *addr) { struct vmap_area *va; - might_sleep(); - va = find_vmap_area((unsigned long)addr); if (va && va->flags & VM_VM_AREA) { struct vm_struct *vm = va->vm; -- 1.8.3.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org