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Groups > linux.kernel > #1358843

[PATCH 3.12 20/58] Revert "jffs2: Fix lock acquisition order bug in jffs2_write_begin"

From Jiri Slaby <jslaby@suse.cz>
Newsgroups linux.kernel
Subject [PATCH 3.12 20/58] Revert "jffs2: Fix lock acquisition order bug in jffs2_write_begin"
Date 2016-03-16 12:10 +0100
Message-ID <rdhuW-896-37@gated-at.bofh.it> (permalink)
References <rdhlg-7Px-15@gated-at.bofh.it>
Organization linux.* mail to news gateway

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From: Thomas Betker <thomas.betker@rohde-schwarz.com>

3.12-stable review patch.  If anyone has any objections, please let me know.

===============

commit 157078f64b8a9cd7011b6b900b2f2498df850748 upstream.

This reverts commit 5ffd3412ae55
("jffs2: Fix lock acquisition order bug in jffs2_write_begin").

The commit modified jffs2_write_begin() to remove a deadlock with
jffs2_garbage_collect_live(), but this introduced new deadlocks found
by multiple users. page_lock() actually has to be called before
mutex_lock(&c->alloc_sem) or mutex_lock(&f->sem) because
jffs2_write_end() and jffs2_readpage() are called with the page locked,
and they acquire c->alloc_sem and f->sem, resp.

In other words, the lock order in jffs2_write_begin() was correct, and
it is the jffs2_garbage_collect_live() path that has to be changed.

Revert the commit to get rid of the new deadlocks, and to clear the way
for a better fix of the original deadlock.

Reported-by: Deng Chao <deng.chao1@zte.com.cn>
Reported-by: Ming Liu <liu.ming50@gmail.com>
Reported-by: wangzaiwei <wangzaiwei@top-vision.cn>
Signed-off-by: Thomas Betker <thomas.betker@rohde-schwarz.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 fs/jffs2/file.c | 39 ++++++++++++++++++---------------------
 1 file changed, 18 insertions(+), 21 deletions(-)

diff --git a/fs/jffs2/file.c b/fs/jffs2/file.c
index 1506673c087e..60ef3fb707ff 100644
--- a/fs/jffs2/file.c
+++ b/fs/jffs2/file.c
@@ -138,39 +138,33 @@ static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
 	struct page *pg;
 	struct inode *inode = mapping->host;
 	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
-	struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
-	struct jffs2_raw_inode ri;
-	uint32_t alloc_len = 0;
 	pgoff_t index = pos >> PAGE_CACHE_SHIFT;
 	uint32_t pageofs = index << PAGE_CACHE_SHIFT;
 	int ret = 0;
 
-	jffs2_dbg(1, "%s()\n", __func__);
-
-	if (pageofs > inode->i_size) {
-		ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len,
-					  ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE);
-		if (ret)
-			return ret;
-	}
-
-	mutex_lock(&f->sem);
 	pg = grab_cache_page_write_begin(mapping, index, flags);
-	if (!pg) {
-		if (alloc_len)
-			jffs2_complete_reservation(c);
-		mutex_unlock(&f->sem);
+	if (!pg)
 		return -ENOMEM;
-	}
 	*pagep = pg;
 
-	if (alloc_len) {
+	jffs2_dbg(1, "%s()\n", __func__);
+
+	if (pageofs > inode->i_size) {
 		/* Make new hole frag from old EOF to new page */
+		struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
+		struct jffs2_raw_inode ri;
 		struct jffs2_full_dnode *fn;
+		uint32_t alloc_len;
 
 		jffs2_dbg(1, "Writing new hole frag 0x%x-0x%x between current EOF and new page\n",
 			  (unsigned int)inode->i_size, pageofs);
 
+		ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len,
+					  ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE);
+		if (ret)
+			goto out_page;
+
+		mutex_lock(&f->sem);
 		memset(&ri, 0, sizeof(ri));
 
 		ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
@@ -197,6 +191,7 @@ static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
 		if (IS_ERR(fn)) {
 			ret = PTR_ERR(fn);
 			jffs2_complete_reservation(c);
+			mutex_unlock(&f->sem);
 			goto out_page;
 		}
 		ret = jffs2_add_full_dnode_to_inode(c, f, fn);
@@ -211,10 +206,12 @@ static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
 			jffs2_mark_node_obsolete(c, fn->raw);
 			jffs2_free_full_dnode(fn);
 			jffs2_complete_reservation(c);
+			mutex_unlock(&f->sem);
 			goto out_page;
 		}
 		jffs2_complete_reservation(c);
 		inode->i_size = pageofs;
+		mutex_unlock(&f->sem);
 	}
 
 	/*
@@ -223,18 +220,18 @@ static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
 	 * case of a short-copy.
 	 */
 	if (!PageUptodate(pg)) {
+		mutex_lock(&f->sem);
 		ret = jffs2_do_readpage_nolock(inode, pg);
+		mutex_unlock(&f->sem);
 		if (ret)
 			goto out_page;
 	}
-	mutex_unlock(&f->sem);
 	jffs2_dbg(1, "end write_begin(). pg->flags %lx\n", pg->flags);
 	return ret;
 
 out_page:
 	unlock_page(pg);
 	page_cache_release(pg);
-	mutex_unlock(&f->sem);
 	return ret;
 }
 
-- 
2.7.3

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[PATCH 3.12 00/58] 3.12.57-stable review Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:00 +0100
  [PATCH 3.12 01/58] nfsd: fix problem with setting ACL on directories Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:00 +0100
    [PATCH 3.12 44/58] KVM: x86: move steal time initialization to vcpu entry time Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
    [PATCH 3.12 48/58] efi: Make our variable validation list include the guid Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
    [PATCH 3.12 15/58] x86/entry/compat: Add missing CLAC to entry_INT80_32 Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
    [PATCH 3.12 34/58] MIPS: traps: Fix SIGFPE information leak from `do_ov' and `do_trap_or_bp' Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
    [PATCH 3.12 29/58] ALSA: hdspm: Fix zero-division Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
    [PATCH 3.12 43/58] powerpc: Fix dedotify for binutils >= 2.26 Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
    [PATCH 3.12 40/58] ASoC: wm8958: Fix enum ctl accesses in a wrong type Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
    [PATCH 3.12 37/58] KVM: VMX: disable PEBS before a guest entry Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
    [PATCH 3.12 42/58] mac80211: minstrel_ht: set default tx aggregation timeout to 0 Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
    [PATCH 3.12 47/58] efi: Do variable name validation tests in utf8 Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
    [PATCH 3.12 33/58] USB: serial: option: add support for Quectel UC20 Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
    [PATCH 3.12 57/58] xen/pciback: Don't allow MSI-X ops if PCI_COMMAND_MEMORY is not set. Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
    [PATCH 3.12 27/58] ALSA: hdspm: Fix wrong boolean ctl value accesses Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
    [PATCH 3.12 13/58] CIFS: Fix SMB2+ interim response processing for read requests Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
    [PATCH 3.12 46/58] efi: Use ucs2_as_utf8 in efivarfs instead of open coding a bad version Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
    [PATCH 3.12 20/58] Revert "jffs2: Fix lock acquisition order bug in jffs2_write_begin" Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
    [PATCH 3.12 45/58] lib/ucs2_string: Add ucs2 -> utf8 helper functions Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
    [PATCH 3.12 38/58] tracing: Fix check for cpu online when event is disabled Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
    [PATCH 3.12 12/58] cifs: fix out-of-bounds access in lease parsing Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
    [PATCH 3.12 28/58] ALSA: hdsp: Fix wrong boolean ctl value accesses Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
    [PATCH 3.12 36/58] Revert "drm/radeon: hold reference to fences in radeon_sa_bo_new" Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
      Re: [PATCH 3.12 36/58] Revert "drm/radeon: hold reference to fences  in radeon_sa_bo_new" Nicolai Hähnle <nicolai.haehnle@amd.com> - 2016-03-16 20:50 +0100
    [PATCH 3.12 53/58] xen/pciback: Return error on XEN_PCI_OP_enable_msi when device has MSI or MSI-X enabled Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
    [PATCH 3.12 56/58] xen/pciback: For XEN_PCI_OP_disable_msi[|x] only disable if device has MSI(X) enabled. Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
    [PATCH 3.12 39/58] ASoC: wm8994: Fix enum ctl accesses in a wrong type Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
    [PATCH 3.12 50/58] efi: Add pstore variables to the deletion whitelist Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
    [PATCH 3.12 58/58] xen/pciback: Check PF instead of VF for PCI_COMMAND_MEMORY Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
    [PATCH 3.12 55/58] xen/pciback: Do not install an IRQ handler for MSI interrupts. Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
    [PATCH 3.12 32/58] USB: serial: option: add support for Telit LE922 PID 0x1045 Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
    [PATCH 3.12 35/58] ubi: Fix out of bounds write in volume update code Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
    [PATCH 3.12 41/58] wext: fix message delay/ordering Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
    [PATCH 3.12 49/58] efi: Make efivarfs entries immutable by default Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
    [PATCH 3.12 31/58] USB: cp210x: Add ID for Parrot NMEA GPS Flight Recorder Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
    [PATCH 3.12 54/58] xen/pciback: Return error on XEN_PCI_OP_enable_msix when device has MSI or MSI-X enabled Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
    [PATCH 3.12 52/58] modules: fix longstanding /proc/kallsyms vs module insertion race. Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
    [PATCH 3.12 51/58] lib/ucs2_string: Correct ucs2 -> utf8 conversion Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:10 +0100
    [PATCH 3.12 16/58] drm/ast: Fix incorrect register check for DRAM width Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:20 +0100
    [PATCH 3.12 21/58] jffs2: Fix page lock / f->sem deadlock Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:20 +0100
    [PATCH 3.12 07/58] [media] usbvision fix overflow of interfaces array Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:20 +0100
    [PATCH 3.12 04/58] USB: cp210x: flush device queues at close Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:20 +0100
    [PATCH 3.12 18/58] libata: Align ata_device's id on a cacheline Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:20 +0100
    [PATCH 3.12 11/58] genksyms: Handle string literals with spaces in reference files Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:20 +0100
    [PATCH 3.12 17/58] libata: fix HDIO_GET_32BIT ioctl Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:20 +0100
    [PATCH 3.12 09/58] ixgbe: use correct FCoE DDP max check Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:20 +0100
    [PATCH 3.12 10/58] ixgbe: fix broken PFC with X550 Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:20 +0100
    [PATCH 3.12 26/58] ALSA: seq: oss: Don't drain at closing a client Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:20 +0100
    [PATCH 3.12 23/58] ALSA: ctl: Fix ioctls for X32 ABI Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:20 +0100
    [PATCH 3.12 02/58] unix: properly account for FDs passed over unix sockets Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:20 +0100
    [PATCH 3.12 25/58] ALSA: timer: Fix ioctls for X32 ABI Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:20 +0100
    [PATCH 3.12 05/58] USB: cp210x: relocate private data from USB interface to port Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:20 +0100
    [PATCH 3.12 19/58] PM / sleep / x86: Fix crash on graph trace through x86 suspend Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:20 +0100
    [PATCH 3.12 24/58] ALSA: rawmidi: Fix ioctls X32 ABI Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:20 +0100
    [PATCH 3.12 14/58] iommu/amd: Fix boot warning when device 00:00.0 is not iommu covered Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:20 +0100
    [PATCH 3.12 22/58] Fix directory hardlinks from deleted directories Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:20 +0100
    [PATCH 3.12 30/58] ALSA: timer: Fix broken compat timer user status ioctl Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:20 +0100
    [PATCH 3.12 06/58] USB: cp210x: work around cp2108 GET_LINE_CTL bug Jiri Slaby <jslaby@suse.cz> - 2016-03-16 12:20 +0100
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  Re: [PATCH 3.12 00/58] 3.12.57-stable review Shuah Khan <shuahkh@osg.samsung.com> - 2016-03-16 16:50 +0100
  Re: [PATCH 3.12 00/58] 3.12.57-stable review Guenter Roeck <linux@roeck-us.net> - 2016-03-16 19:00 +0100
    Re: [PATCH 3.12 00/58] 3.12.57-stable review Jiri Slaby <jslaby@suse.cz> - 2016-03-16 19:20 +0100
      Re: [PATCH 3.12 00/58] 3.12.57-stable review Guenter Roeck <linux@roeck-us.net> - 2016-03-17 04:30 +0100

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