commit 2e898e4c0a3897ccd434adac5abb8330194f527b upstream.
lock_page_memcg()/unlock_page_memcg() use spin_lock_irqsave/restore() if
the page's memcg is undergoing move accounting, which occurs when a
process leaves its memcg for a new one that has
memory.move_charge_at_immigrate set.
unlocked_inode_to_wb_begin,end() use spin_lock_irq/spin_unlock_irq() if
the given inode is switching writeback domains. Switches occur when
enough writes are issued from a new domain.
This existing pattern is thus suspicious:
lock_page_memcg(page);
unlocked_inode_to_wb_begin(inode, &locked);
...
unlocked_inode_to_wb_end(inode, locked);
unlock_page_memcg(page);
If both inode switch and process memcg migration are both in-flight then
unlocked_inode_to_wb_end() will unconditionally enable interrupts while
still holding the lock_page_memcg() irq spinlock. This suggests the
possibility of deadlock if an interrupt occurs before unlock_page_memcg().
truncate
__cancel_dirty_page
lock_page_memcg
unlocked_inode_to_wb_begin
unlocked_inode_to_wb_end
<interrupts mistakenly enabled>
<interrupt>
end_page_writeback
test_clear_page_writeback
lock_page_memcg
<deadlock>
unlock_page_memcg
Due to configuration limitations this deadlock is not currently possible
because we don't mix cgroup writeback (a cgroupv2 feature) and
memory.move_charge_at_immigrate (a cgroupv1 feature).
If the kernel is hacked to always claim inode switching and memcg
moving_account, then this script triggers lockup in less than a minute:
cd /mnt/cgroup/memory
mkdir a b
echo 1 > a/memory.move_charge_at_immigrate
echo 1 > b/memory.move_charge_at_immigrate
(
echo $BASHPID > a/cgroup.procs
while true; do
dd if=/dev/zero of=/mnt/big bs=1M count=256
done
) &
while true; do
sync
done &
sleep 1h &
SLEEP=$!
while true; do
echo $SLEEP > a/cgroup.procs
echo $SLEEP > b/cgroup.procs
done
The deadlock does not seem possible, so it's debatable if there's any
reason to modify the kernel. I suggest we should to prevent future
surprises. And Wang Long said "this deadlock occurs three times in our
environment", so there's more reason to apply this, even to stable.
Stable 4.4 has minor conflicts applying this patch. For a clean 4.4 patch
see "[PATCH for-4.4] writeback: safer lock nesting"
https://lkml.org/lkml/2018/4/11/146
Wang Long said "this deadlock occurs three times in our environment"
[gthelen@google.com: v4]
Link: http://lkml.kernel.org/r/20180411084653.254724-1-gthelen@google.com
[akpm@linux-foundation.org: comment tweaks, struct initialization simplification]
Change-Id: Ibb773e8045852978f6207074491d262f1b3fb613
Link: http://lkml.kernel.org/r/20180410005908.167976-1-gthelen@google.com
Fixes: 682aa8e1a6a1 ("writeback: implement unlocked_inode_to_wb transaction and use it for stat updates")
Signed-off-by: Greg Thelen <gthelen@google.com>
Reported-by: Wang Long <wanglong19@meituan.com>
Acked-by: Wang Long <wanglong19@meituan.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: <stable@vger.kernel.org> [v4.2+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[natechancellor: Adjust context due to lack of b93b016313b3b]
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit d848e5f8e1ebdb227d045db55fe4f825e82965fa upstream. Add a new ioctl which forces the the crng to be reseeded. Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 40cab6e88cb0b6c56d3f30b7491a20e803f948f6 upstream.
OSS PCM stream management isn't modal but it allows ioctls issued at
any time for changing the parameters. In the previous hardening
patch ("ALSA: pcm: Avoid potential races between OSS ioctls and
read/write"), we covered these races and prevent the corruption by
protecting the concurrent accesses via params_lock mutex. However,
this means that some ioctls that try to change the stream parameter
(e.g. channels or format) would be blocked until the read/write
finishes, and it may take really long.
Basically changing the parameter while reading/writing is an invalid
operation, hence it's even more user-friendly from the API POV if it
returns -EBUSY in such a situation.
This patch adds such checks in the relevant ioctls with the addition
of read/write access refcount.
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 55a5fcafe3a94e8a0777bb993d09107d362258d2 upstream.
Just add binding for a fixed-factor clock axisel_d4, which would be
referenced by PWM devices on MT7623 or MT2701 SoC.
Cc: stable@vger.kernel.org
Fixes: 1de9b21633d6 ("clk: mediatek: Add dt-bindings for MT2701 clocks")
Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: devicetree@vger.kernel.org
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 6de0b13cc0b4ba10e98a9263d7a83b940720b77a upstream. When size is negative, calling memset will make segment fault. Declare the size as type u32 to keep memset safe. size in struct hid_report is unsigned, fix return type of hid_report_len to u32. Cc: stable@vger.kernel.org Signed-off-by: Aaron Ma <aaron.ma@canonical.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 28b0f8a6962a24ed21737578f3b1b07424635c9e upstream.
A tty is hung up by __tty_hangup() setting file->f_op to
hung_up_tty_fops, which is skipped on ttys whose write operation isn't
tty_write(). This means that, for example, /dev/console whose write
op is redirected_tty_write() is never actually marked hung up.
Because n_tty_read() uses the hung up status to decide whether to
abort the waiting readers, the lack of hung-up marking can lead to the
following scenario.
1. A session contains two processes. The leader and its child. The
child ignores SIGHUP.
2. The leader exits and starts disassociating from the controlling
terminal (/dev/console).
3. __tty_hangup() skips setting f_op to hung_up_tty_fops.
4. SIGHUP is delivered and ignored.
5. tty_ldisc_hangup() is invoked. It wakes up the waits which should
clear the read lockers of tty->ldisc_sem.
6. The reader wakes up but because tty_hung_up_p() is false, it
doesn't abort and goes back to sleep while read-holding
tty->ldisc_sem.
7. The leader progresses to tty_ldisc_lock() in tty_ldisc_hangup()
and is now stuck in D sleep indefinitely waiting for
tty->ldisc_sem.
The following is Alan's explanation on why some ttys aren't hung up.
http://lkml.kernel.org/r/20171101170908.6ad08580@alans-desktop
1. It broke the serial consoles because they would hang up and close
down the hardware. With tty_port that *should* be fixable properly
for any cases remaining.
2. The console layer was (and still is) completely broken and doens't
refcount properly. So if you turn on console hangups it breaks (as
indeed does freeing consoles and half a dozen other things).
As neither can be fixed quickly, this patch works around the problem
by introducing a new flag, TTY_HUPPING, which is used solely to tell
n_tty_read() that hang-up is in progress for the console and the
readers should be aborted regardless of the hung-up status of the
device.
The following is a sample hung task warning caused by this issue.
INFO: task agetty:2662 blocked for more than 120 seconds.
Not tainted 4.11.3-dbg-tty-lockup-02478-gfd6c7ee-dirty #28
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
0 2662 1 0x00000086
Call Trace:
__schedule+0x267/0x890
schedule+0x36/0x80
schedule_timeout+0x23c/0x2e0
ldsem_down_write+0xce/0x1f6
tty_ldisc_lock+0x16/0x30
tty_ldisc_hangup+0xb3/0x1b0
__tty_hangup+0x300/0x410
disassociate_ctty+0x6c/0x290
do_exit+0x7ef/0xb00
do_group_exit+0x3f/0xa0
get_signal+0x1b3/0x5d0
do_signal+0x28/0x660
exit_to_usermode_loop+0x46/0x86
do_syscall_64+0x9c/0xb0
entry_SYSCALL64_slow_path+0x25/0x25
The following is the repro. Run "$PROG /dev/console". The parent
process hangs in D state.
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <signal.h>
#include <time.h>
#include <termios.h>
int main(int argc, char **argv)
{
struct sigaction sact = { .sa_handler = SIG_IGN };
struct timespec ts1s = { .tv_sec = 1 };
pid_t pid;
int fd;
if (argc < 2) {
fprintf(stderr, "test-hung-tty /dev/$TTY\n");
return 1;
}
/* fork a child to ensure that it isn't already the session leader */
pid = fork();
if (pid < 0) {
perror("fork");
return 1;
}
if (pid > 0) {
/* top parent, wait for everyone */
while (waitpid(-1, NULL, 0) >= 0)
;
if (errno != ECHILD)
perror("waitpid");
return 0;
}
/* new session, start a new session and set the controlling tty */
if (setsid() < 0) {
perror("setsid");
return 1;
}
fd = open(argv[1], O_RDWR);
if (fd < 0) {
perror("open");
return 1;
}
if (ioctl(fd, TIOCSCTTY, 1) < 0) {
perror("ioctl");
return 1;
}
/* fork a child, sleep a bit and exit */
pid = fork();
if (pid < 0) {
perror("fork");
return 1;
}
if (pid > 0) {
nanosleep(&ts1s, NULL);
printf("Session leader exiting\n");
exit(0);
}
/*
* The child ignores SIGHUP and keeps reading from the controlling
* tty. Because SIGHUP is ignored, the child doesn't get killed on
* parent exit and the bug in n_tty makes the read(2) block the
* parent's control terminal hangup attempt. The parent ends up in
* D sleep until the child is explicitly killed.
*/
sigaction(SIGHUP, &sact, NULL);
printf("Child reading tty\n");
while (1) {
char buf[1024];
if (read(fd, buf, sizeof(buf)) < 0) {
perror("read");
return 1;
}
}
return 0;
}
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Alan Cox <alan@llwyncelyn.cymru>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 3f01ddb962dc506916c243f9524e8bef97119b77 ] On receiving a packet the state index points to the rstate which must be used to fill up IP and TCP headers. But if the state index points to a rstate which is unitialized, i.e. filled with zeros, it gets stuck in an infinite loop inside ip_fast_csum trying to compute the ip checsum of a header with zero length. 89.666953: <2> [<ffffff9dd3e94d38>] slhc_uncompress+0x464/0x468 89.666965: <2> [<ffffff9dd3e87d88>] ppp_receive_nonmp_frame+0x3b4/0x65c 89.666978: <2> [<ffffff9dd3e89dd4>] ppp_receive_frame+0x64/0x7e0 89.666991: <2> [<ffffff9dd3e8a708>] ppp_input+0x104/0x198 89.667005: <2> [<ffffff9dd3e93868>] pppopns_recv_core+0x238/0x370 89.667027: <2> [<ffffff9dd4428fc8>] __sk_receive_skb+0xdc/0x250 89.667040: <2> [<ffffff9dd3e939e4>] pppopns_recv+0x44/0x60 89.667053: <2> [<ffffff9dd4426848>] __sock_queue_rcv_skb+0x16c/0x24c 89.667065: <2> [<ffffff9dd4426954>] sock_queue_rcv_skb+0x2c/0x38 89.667085: <2> [<ffffff9dd44f7358>] raw_rcv+0x124/0x154 89.667098: <2> [<ffffff9dd44f7568>] raw_local_deliver+0x1e0/0x22c 89.667117: <2> [<ffffff9dd44c8ba0>] ip_local_deliver_finish+0x70/0x24c 89.667131: <2> [<ffffff9dd44c92f4>] ip_local_deliver+0x100/0x10c ./scripts/faddr2line vmlinux slhc_uncompress+0x464/0x468 output: ip_fast_csum at arch/arm64/include/asm/checksum.h:40 (inlined by) slhc_uncompress at drivers/net/slip/slhc.c:615 Adding a variable to indicate if the current rstate is initialized. If such a packet arrives, move to toss state. Signed-off-by: Tejaswi Tanikella <tejaswit@codeaurora.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 082f2300cfa1a3d9d5221c38c5eba85d4ab98bd8 upstream.
Local random address needs to be updated before creating connection if
RPA from LE Direct Advertising Report was resolved in host. Otherwise
remote device might ignore connection request due to address mismatch.
This was affecting following qualification test cases:
GAP/CONN/SCEP/BV-03-C, GAP/CONN/GCEP/BV-05-C, GAP/CONN/DCEP/BV-05-C
Before patch:
< HCI Command: LE Set Random Address (0x08|0x0005) plen 6 #11350 [hci0] 84680.231216
Address: 56:BC:E8:24:11:68 (Resolvable)
Identity type: Random (0x01)
Identity: F2:F1:06:3D:9C:42 (Static)
> HCI Event: Command Complete (0x0e) plen 4 #11351 [hci0] 84680.246022
LE Set Random Address (0x08|0x0005) ncmd 1
Status: Success (0x00)
< HCI Command: LE Set Scan Parameters (0x08|0x000b) plen 7 #11352 [hci0] 84680.246417
Type: Passive (0x00)
Interval: 60.000 msec (0x0060)
Window: 30.000 msec (0x0030)
Own address type: Random (0x01)
Filter policy: Accept all advertisement, inc. directed unresolved RPA (0x02)
> HCI Event: Command Complete (0x0e) plen 4 #11353 [hci0] 84680.248854
LE Set Scan Parameters (0x08|0x000b) ncmd 1
Status: Success (0x00)
< HCI Command: LE Set Scan Enable (0x08|0x000c) plen 2 #11354 [hci0] 84680.249466
Scanning: Enabled (0x01)
Filter duplicates: Enabled (0x01)
> HCI Event: Command Complete (0x0e) plen 4 #11355 [hci0] 84680.253222
LE Set Scan Enable (0x08|0x000c) ncmd 1
Status: Success (0x00)
> HCI Event: LE Meta Event (0x3e) plen 18 #11356 [hci0] 84680.458387
LE Direct Advertising Report (0x0b)
Num reports: 1
Event type: Connectable directed - ADV_DIRECT_IND (0x01)
Address type: Random (0x01)
Address: 53:38:DA:46:8C:45 (Resolvable)
Identity type: Public (0x00)
Identity: 11:22:33:44:55:66 (OUI 11-22-33)
Direct address type: Random (0x01)
Direct address: 7C:D6:76:8C:DF:82 (Resolvable)
Identity type: Random (0x01)
Identity: F2:F1:06:3D:9C:42 (Static)
RSSI: -74 dBm (0xb6)
< HCI Command: LE Set Scan Enable (0x08|0x000c) plen 2 #11357 [hci0] 84680.458737
Scanning: Disabled (0x00)
Filter duplicates: Disabled (0x00)
> HCI Event: Command Complete (0x0e) plen 4 #11358 [hci0] 84680.469982
LE Set Scan Enable (0x08|0x000c) ncmd 1
Status: Success (0x00)
< HCI Command: LE Create Connection (0x08|0x000d) plen 25 #11359 [hci0] 84680.470444
Scan interval: 60.000 msec (0x0060)
Scan window: 60.000 msec (0x0060)
Filter policy: White list is not used (0x00)
Peer address type: Random (0x01)
Peer address: 53:38:DA:46:8C:45 (Resolvable)
Identity type: Public (0x00)
Identity: 11:22:33:44:55:66 (OUI 11-22-33)
Own address type: Random (0x01)
Min connection interval: 30.00 msec (0x0018)
Max connection interval: 50.00 msec (0x0028)
Connection latency: 0 (0x0000)
Supervision timeout: 420 msec (0x002a)
Min connection length: 0.000 msec (0x0000)
Max connection length: 0.000 msec (0x0000)
> HCI Event: Command Status (0x0f) plen 4 #11360 [hci0] 84680.474971
LE Create Connection (0x08|0x000d) ncmd 1
Status: Success (0x00)
< HCI Command: LE Create Connection Cancel (0x08|0x000e) plen 0 #11361 [hci0] 84682.545385
> HCI Event: Command Complete (0x0e) plen 4 #11362 [hci0] 84682.551014
LE Create Connection Cancel (0x08|0x000e) ncmd 1
Status: Success (0x00)
> HCI Event: LE Meta Event (0x3e) plen 19 #11363 [hci0] 84682.551074
LE Connection Complete (0x01)
Status: Unknown Connection Identifier (0x02)
Handle: 0
Role: Master (0x00)
Peer address type: Public (0x00)
Peer address: 00:00:00:00:00:00 (OUI 00-00-00)
Connection interval: 0.00 msec (0x0000)
Connection latency: 0 (0x0000)
Supervision timeout: 0 msec (0x0000)
Master clock accuracy: 0x00
After patch:
< HCI Command: LE Set Scan Parameters (0x08|0x000b) plen 7 #210 [hci0] 667.152459
Type: Passive (0x00)
Interval: 60.000 msec (0x0060)
Window: 30.000 msec (0x0030)
Own address type: Random (0x01)
Filter policy: Accept all advertisement, inc. directed unresolved RPA (0x02)
> HCI Event: Command Complete (0x0e) plen 4 #211 [hci0] 667.153613
LE Set Scan Parameters (0x08|0x000b) ncmd 1
Status: Success (0x00)
< HCI Command: LE Set Scan Enable (0x08|0x000c) plen 2 #212 [hci0] 667.153704
Scanning: Enabled (0x01)
Filter duplicates: Enabled (0x01)
> HCI Event: Command Complete (0x0e) plen 4 #213 [hci0] 667.154584
LE Set Scan Enable (0x08|0x000c) ncmd 1
Status: Success (0x00)
> HCI Event: LE Meta Event (0x3e) plen 18 #214 [hci0] 667.182619
LE Direct Advertising Report (0x0b)
Num reports: 1
Event type: Connectable directed - ADV_DIRECT_IND (0x01)
Address type: Random (0x01)
Address: 50:52:D9:A6:48:A0 (Resolvable)
Identity type: Public (0x00)
Identity: 11:22:33:44:55:66 (OUI 11-22-33)
Direct address type: Random (0x01)
Direct address: 7C:C1:57:A5:B7:A8 (Resolvable)
Identity type: Random (0x01)
Identity: F4:28:73:5D:38:B0 (Static)
RSSI: -70 dBm (0xba)
< HCI Command: LE Set Scan Enable (0x08|0x000c) plen 2 #215 [hci0] 667.182704
Scanning: Disabled (0x00)
Filter duplicates: Disabled (0x00)
> HCI Event: Command Complete (0x0e) plen 4 #216 [hci0] 667.183599
LE Set Scan Enable (0x08|0x000c) ncmd 1
Status: Success (0x00)
< HCI Command: LE Set Random Address (0x08|0x0005) plen 6 #217 [hci0] 667.183645
Address: 7C:C1:57:A5:B7:A8 (Resolvable)
Identity type: Random (0x01)
Identity: F4:28:73:5D:38:B0 (Static)
> HCI Event: Command Complete (0x0e) plen 4 #218 [hci0] 667.184590
LE Set Random Address (0x08|0x0005) ncmd 1
Status: Success (0x00)
< HCI Command: LE Create Connection (0x08|0x000d) plen 25 #219 [hci0] 667.184613
Scan interval: 60.000 msec (0x0060)
Scan window: 60.000 msec (0x0060)
Filter policy: White list is not used (0x00)
Peer address type: Random (0x01)
Peer address: 50:52:D9:A6:48:A0 (Resolvable)
Identity type: Public (0x00)
Identity: 11:22:33:44:55:66 (OUI 11-22-33)
Own address type: Random (0x01)
Min connection interval: 30.00 msec (0x0018)
Max connection interval: 50.00 msec (0x0028)
Connection latency: 0 (0x0000)
Supervision timeout: 420 msec (0x002a)
Min connection length: 0.000 msec (0x0000)
Max connection length: 0.000 msec (0x0000)
> HCI Event: Command Status (0x0f) plen 4 #220 [hci0] 667.186558
LE Create Connection (0x08|0x000d) ncmd 1
Status: Success (0x00)
> HCI Event: LE Meta Event (0x3e) plen 19 #221 [hci0] 667.485824
LE Connection Complete (0x01)
Status: Success (0x00)
Handle: 0
Role: Master (0x00)
Peer address type: Random (0x01)
Peer address: 50:52:D9:A6:48:A0 (Resolvable)
Identity type: Public (0x00)
Identity: 11:22:33:44:55:66 (OUI 11-22-33)
Connection interval: 50.00 msec (0x0028)
Connection latency: 0 (0x0000)
Supervision timeout: 420 msec (0x002a)
Master clock accuracy: 0x07
@ MGMT Event: Device Connected (0x000b) plen 13 {0x0002} [hci0] 667.485996
LE Address: 11:22:33:44:55:66 (OUI 11-22-33)
Flags: 0x00000000
Data length: 0
Signed-off-by: Szymon Janc <szymon.janc@codecoup.pl>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
From: Marc Zyngier <marc.zyngier@arm.com> commit f2d3b2e8759a5833df6f022e42df2d581e6d843c upstream. One of the major improvement of SMCCC v1.1 is that it only clobbers the first 4 registers, both on 32 and 64bit. This means that it becomes very easy to provide an inline version of the SMC call primitive, and avoid performing a function call to stash the registers that would otherwise be clobbered by SMCCC v1.0. Reviewed-by: Robin Murphy <robin.murphy@arm.com> Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Mark Rutland <mark.rutland@arm.com> [v4.9 backport] Tested-by: Greg Hackmann <ghackmann@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
From: Marc Zyngier <marc.zyngier@arm.com> commit ded4c39e93f3b72968fdb79baba27f3b83dad34c upstream. Function identifiers are a 32bit, unsigned quantity. But we never tell so to the compiler, resulting in the following: 4ac: b26187e0 mov x0, #0xffffffff80000001 We thus rely on the firmware narrowing it for us, which is not always a reasonable expectation. Cc: stable@vger.kernel.org Reported-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Reviewed-by: Robin Murphy <robin.murphy@arm.com> Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Mark Rutland <mark.rutland@arm.com> [v4.9 backport] Tested-by: Greg Hackmann <ghackmann@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>