From: Willy Tarreau <w@1wt.eu>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Andrew Morton <akpm@linux-foundation.org>,
Maxim Patlasov <mpatlasov@parallels.com>,
Konstantin Khlebnikov <khlebnikov@yandex-team.ru>,
Roman Gushchin <klamm@yandex-team.ru>,
Miklos Szeredi <miklos@szeredi.hu>,
Ben Hutchings <ben@decadent.org.uk>, Willy Tarreau <w@1wt.eu>
Subject: [PATCH 2.6.32 14/42] fuse: break infinite loop in fuse_fill_write_pages()
Date: Sat, 23 Jan 2016 15:12:35 +0100 [thread overview]
Message-ID: <20160123141222.586450489@1wt.eu> (raw)
In-Reply-To: <aa387f55227cb730b41e3d621bf460ff@local>
2.6.32-longterm review patch. If anyone has any objections, please let me know.
------------------
From: Roman Gushchin <klamm@yandex-team.ru>
commit 3ca8138f014a913f98e6ef40e939868e1e9ea876 upstream.
I got a report about unkillable task eating CPU. Further
investigation shows, that the problem is in the fuse_fill_write_pages()
function. If iov's first segment has zero length, we get an infinite
loop, because we never reach iov_iter_advance() call.
Fix this by calling iov_iter_advance() before repeating an attempt to
copy data from userspace.
A similar problem is described in 124d3b7041f ("fix writev regression:
pan hanging unkillable and un-straceable"). If zero-length segmend
is followed by segment with invalid address,
iov_iter_fault_in_readable() checks only first segment (zero-length),
iov_iter_copy_from_user_atomic() skips it, fails at second and
returns zero -> goto again without skipping zero-length segment.
Patch calls iov_iter_advance() before goto again: we'll skip zero-length
segment at second iteraction and iov_iter_fault_in_readable() will detect
invalid address.
Special thanks to Konstantin Khlebnikov, who helped a lot with the commit
description.
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Maxim Patlasov <mpatlasov@parallels.com>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Roman Gushchin <klamm@yandex-team.ru>
Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Fixes: ea9b9907b82a ("fuse: implement perform_write")
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
(cherry picked from commit a5b234167a1ff46f311f5835828eec2f971b9bb4)
[wt: adjusted context, as commit 478e0841b from 3.1 was never backported
to call mark_page_accessed() eventhough it seems it should have been]
Signed-off-by: Willy Tarreau <w@1wt.eu>
---
fs/fuse/file.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 102d582..c8dc4f3 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -885,6 +885,7 @@ static ssize_t fuse_fill_write_pages(struct fuse_req *req,
pagefault_enable();
flush_dcache_page(page);
+ iov_iter_advance(ii, tmp);
if (!tmp) {
unlock_page(page);
page_cache_release(page);
@@ -896,7 +897,6 @@ static ssize_t fuse_fill_write_pages(struct fuse_req *req,
req->pages[req->num_pages] = page;
req->num_pages++;
- iov_iter_advance(ii, tmp);
count += tmp;
pos += tmp;
offset += tmp;
--
1.7.12.2.21.g234cd45.dirty
next prev parent reply other threads:[~2016-01-23 14:46 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <aa387f55227cb730b41e3d621bf460ff@local>
2016-01-23 14:12 ` [PATCH 2.6.32 01/42] ip6mr: call del_timer_sync() in ip6mr_free_table() Willy Tarreau
2016-01-23 14:12 ` [PATCH 2.6.32 02/42] isdn_ppp: Add checks for allocation failure in isdn_ppp_open() Willy Tarreau
2016-01-23 14:12 ` [PATCH 2.6.32 04/42] RDS: fix race condition when sending a message on unbound socket Willy Tarreau
2016-01-23 14:12 ` [PATCH 2.6.32 05/42] unix: avoid use-after-free in ep_remove_wait_queue Willy Tarreau
2016-01-23 14:12 ` [PATCH 2.6.32 06/42] ext4: Fix null dereference in ext4_fill_super() Willy Tarreau
2016-01-23 14:12 ` [PATCH 2.6.32 07/42] Revert "net: add length argument to skb_copy_and_csum_datagram_iovec" Willy Tarreau
2016-01-23 14:12 ` [PATCH 2.6.32 08/42] udp: properly support MSG_PEEK with truncated buffers Willy Tarreau
2016-01-23 14:12 ` [PATCH 2.6.32 09/42] KEYS: Fix race between read and revoke Willy Tarreau
2016-01-23 14:12 ` [PATCH 2.6.32 11/42] net: fix warnings in make htmldocs by moving macro definition out of field declaration Willy Tarreau
2016-01-23 14:12 ` [PATCH 2.6.32 12/42] bluetooth: Validate socket address length in sco_sock_bind() Willy Tarreau
2016-01-23 14:12 ` [PATCH 2.6.32 13/42] sctp: translate host order to network order when setting a hmacid Willy Tarreau
2016-01-23 14:12 ` Willy Tarreau [this message]
2016-01-23 14:12 ` [PATCH 2.6.32 15/42] fix sysvfs symlinks Willy Tarreau
2016-01-23 14:12 ` [PATCH 2.6.32 16/42] vfs: Avoid softlockups with sendfile(2) Willy Tarreau
2016-01-23 14:12 ` [PATCH 2.6.32 17/42] ext4: Fix handling of extended tv_sec Willy Tarreau
2016-01-23 14:12 ` [PATCH 2.6.32 18/42] nfs: if we have no valid attrs, then dont declare the attribute cache valid Willy Tarreau
2016-01-23 14:12 ` [PATCH 2.6.32 19/42] wan/x25: Fix use-after-free in x25_asy_open_tty() Willy Tarreau
2016-01-23 14:12 ` [PATCH 2.6.32 20/42] ipv4: igmp: Allow removing groups from a removed interface Willy Tarreau
2016-01-23 14:12 ` [PATCH 2.6.32 21/42] sched/core: Remove false-positive warning from wake_up_process() Willy Tarreau
2016-01-23 14:12 ` [PATCH 2.6.32 22/42] ipmi: move timer init to before irq is setup Willy Tarreau
2016-01-23 14:12 ` [PATCH 2.6.32 23/42] tcp: initialize tp->copied_seq in case of cross SYN connection Willy Tarreau
2016-01-23 14:12 ` [PATCH 2.6.32 24/42] net, scm: fix PaX detected msg_controllen overflow in scm_detach_fds Willy Tarreau
2016-01-23 14:12 ` [PATCH 2.6.32 25/42] sctp: update the netstamp_needed counter when copying sockets Willy Tarreau
2016-01-23 14:12 ` [PATCH 2.6.32 26/42] af_unix: fix a fatal race with bit fields Willy Tarreau
2016-01-23 14:12 ` [PATCH 2.6.32 27/42] rfkill: copy the name into the rfkill struct Willy Tarreau
2016-01-23 14:12 ` [PATCH 2.6.32 28/42] ses: Fix problems with simple enclosures Willy Tarreau
2016-01-23 14:12 ` [PATCH 2.6.32 29/42] ses: fix additional element traversal bug Willy Tarreau
2016-01-23 14:12 ` [PATCH 2.6.32 30/42] tty: Fix GPF in flush_to_ldisc() Willy Tarreau
2016-01-23 14:12 ` [PATCH 2.6.32 31/42] mISDN: fix a loop count Willy Tarreau
2016-01-23 14:12 ` [PATCH 2.6.32 32/42] ser_gigaset: fix deallocation of platform device structure Willy Tarreau
2016-01-23 14:12 ` [PATCH 2.6.32 33/42] spi: fix parent-device reference leak Willy Tarreau
2016-01-23 14:12 ` [PATCH 2.6.32 34/42] s390/dis: Fix handling of format specifiers Willy Tarreau
2016-01-23 14:12 ` [PATCH 2.6.32 35/42] USB: ipaq.c: fix a timeout loop Willy Tarreau
2016-01-23 14:12 ` [PATCH 2.6.32 36/42] USB: fix invalid memory access in hub_activate() Willy Tarreau
2016-01-23 14:12 ` [PATCH 2.6.32 37/42] MIPS: Fix restart of indirect syscalls Willy Tarreau
2016-01-23 14:12 ` [PATCH 2.6.32 38/42] parisc: Fix syscall restarts Willy Tarreau
2016-01-23 14:13 ` [PATCH 2.6.32 39/42] ipv6/addrlabel: fix ip6addrlbl_get() Willy Tarreau
2016-01-23 14:13 ` [PATCH 2.6.32 40/42] mm/memory_hotplug.c: check for missing sections in test_pages_in_a_zone() Willy Tarreau
2016-01-23 18:13 ` Ben Hutchings
2016-01-23 18:29 ` Willy Tarreau
2016-01-23 19:05 ` Willy Tarreau
2016-01-23 14:13 ` [PATCH 2.6.32 41/42] KVM: x86: Reload pit counters for all channels when restoring state Willy Tarreau
2016-01-23 14:13 ` [PATCH 2.6.32 42/42] kvm: x86: only channel 0 of the i8254 is linked to the HPET Willy Tarreau
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