[PATCH 3.10 14/46] d_walk() might skip too much

From	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Newsgroups	linux.kernel
Subject	[PATCH 3.10 14/46] d_walk() might skip too much
Date	2015-06-03 13:50 +0200
Message-ID	<pxflh-8gc-49@gated-at.bofh.it> (permalink)
References	<pxflf-8gc-5@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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

------------------

From: Al Viro <viro@zeniv.linux.org.uk>

commit 2159184ea01e4ae7d15f2017e296d4bc82d5aeb0 upstream.

when we find that a child has died while we'd been trying to ascend,
we should go into the first live sibling itself, rather than its sibling.

Off-by-one in question had been introduced in "deal with deadlock in
d_walk()" and the fix needs to be backported to all branches this one
has been backported to.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/dcache.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1179,13 +1179,13 @@ ascend:
 		/* might go back up the wrong parent if we have had a rename. */
 		if (!locked && read_seqretry(&rename_lock, seq))
 			goto rename_retry;
-		next = child->d_child.next;
-		while (unlikely(child->d_flags & DCACHE_DENTRY_KILLED)) {
+		/* go into the first sibling still alive */
+		do {
+			next = child->d_child.next;
 			if (next == &this_parent->d_subdirs)
 				goto ascend;
 			child = list_entry(next, struct dentry, d_child);
-			next = next->next;
-		}
+		} while (unlikely(child->d_flags & DCACHE_DENTRY_KILLED));
 		rcu_read_unlock();
 		goto resume;
 	}


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Thread

[PATCH 3.10 00/46] 3.10.80-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 13:50 +0200
  [PATCH 3.10 07/46] net: socket: Fix the wrong returns for recvmsg and sendmsg Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 13:50 +0200
  [PATCH 3.10 42/46] rtlwifi: rtl8192cu: Fix kernel deadlock Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 13:50 +0200
  [PATCH 3.10 36/46] rt2x00: add new rt2800usb device DWA 130 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 13:50 +0200
  [PATCH 3.10 44/46] ACPI / init: Fix the ordering of acpi_reserve_resources() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 13:50 +0200
  [PATCH 3.10 11/46] libceph: request a new osdmap if lingering request maps to no osd Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 13:50 +0200
  [PATCH 3.10 19/46] ASoC: wm8960: fix "RINPUT3" audio route error Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 13:50 +0200
  [PATCH 3.10 23/46] xhci: Solve full event ring by increasing TRBS_PER_SEGMENT to 256 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 13:50 +0200
  [PATCH 3.10 22/46] xhci: fix isoc endpoint dequeue from advancing too far on transaction error Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 13:50 +0200
  [PATCH 3.10 10/46] lguest: fix out-by-one error in address checking. Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 13:50 +0200
  [PATCH 3.10 31/46] mmc: atmel-mci: fix bad variable type for clkdiv Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 13:50 +0200
  [PATCH 3.10 12/46] hwmon: (ntc_thermistor) Ensure iio channel is of type IIO_VOLTAGE Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 13:50 +0200
  [PATCH 3.10 09/46] fs, omfs: add NULL terminator in the end up the token list Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 13:50 +0200
  [PATCH 3.10 15/46] ALSA: hda - Add Conexant codecs CX20721, CX20722, CX20723 and CX20724 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 13:50 +0200
  [PATCH 3.10 16/46] ALSA: hda - Add headphone quirk for Lifebook E752 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 13:50 +0200
  [PATCH 3.10 14/46] d_walk() might skip too much Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 13:50 +0200
  [PATCH 3.10 43/46] Input: elantech - fix semi-mt protocol for v3 HW Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 13:50 +0200
  [PATCH 3.10 46/46] fs/binfmt_elf.c:load_elf_binary(): return -EINVAL on zero-length mappings Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 13:50 +0200
  [PATCH 3.10 24/46] xhci: gracefully handle xhci_irq dead device Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 13:50 +0200
  [PATCH 3.10 01/46] staging: wlags49_h2: fix extern inline functions Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 13:50 +0200
  [PATCH 3.10 37/46] crypto: s390/ghash - Fix incorrect ghash icv buffer handling. Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 13:50 +0200
  [PATCH 3.10 08/46] KVM: MMU: fix CR4.SMEP=1, CR0.WP=0 with shadow pages Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 13:50 +0200
  [PATCH 3.10 45/46] vfs: read file_handle only once in handle_to_path Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 13:50 +0200
  [PATCH 3.10 06/46] kernel: use the gnu89 standard explicitly Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 13:50 +0200
  [PATCH 3.10 18/46] ASoC: uda1380: Avoid accessing i2c bus when codec is disabled Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 13:50 +0200
  [PATCH 3.10 34/46] libata: Add helper to determine when PHY events should be ignored Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 14:00 +0200
  [PATCH 3.10 25/46] USB: visor: Match I330 phone more precisely Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 14:00 +0200
  [PATCH 3.10 20/46] ASoC: wm8994: correct BCLK DIV 348 to 384 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 14:00 +0200
  [PATCH 3.10 04/46] staging: rtl8712, rtl8712: avoid lots of build warnings Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 14:00 +0200
  [PATCH 3.10 32/46] ext4: convert write_begin methods to stable_page_writes semantics Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 14:00 +0200
  [PATCH 3.10 30/46] powerpc: Align TOC to 256 bytes Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 14:00 +0200
  [PATCH 3.10 13/46] lib: Fix strnlen_user() to not touch memory after specified maximum Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 14:00 +0200
  [PATCH 3.10 39/46] ARM: fix missing syscall trace exit Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 14:00 +0200
  [PATCH 3.10 05/46] staging, rtl8192e, LLVMLinux: Remove unused inline prototype Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 14:00 +0200
  [PATCH 3.10 03/46] staging, rtl8192e, LLVMLinux: Change extern inline to static inline Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 14:00 +0200
  [PATCH 3.10 17/46] ASoC: mc13783: Fix wrong mask value used in mc13xxx_reg_rmw() calls Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 14:00 +0200
  [PATCH 3.10 41/46] md/raid5: dont record new size if resize_stripes fails. Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 14:00 +0200
  [PATCH 3.10 26/46] USB: pl2303: Remove support for Samsung I330 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 14:00 +0200
  [PATCH 3.10 29/46] usb: gadget: configfs: Fix interfaces array NULL-termination Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 14:00 +0200
  [PATCH 3.10 33/46] ext4: check for zero length extent explicitly Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 14:00 +0200
  [PATCH 3.10 40/46] svcrpc: fix potential GSSX_ACCEPT_SEC_CONTEXT decoding failures Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 14:00 +0200
  [PATCH 3.10 27/46] USB: cp210x: add ID for KCF Technologies PRN device Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 14:00 +0200
  Re: [PATCH 3.10 00/46] 3.10.80-stable review Shuah Khan <shuahkh@osg.samsung.com> - 2015-06-03 19:00 +0200

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