drm/xen-front: Rework vblank handling #28
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Move from a single vblank timer which handles both vblank emulation and page flip time-outs to a dedicated vblank timer per DRM driver and page flip time-out timer per CRTC. Signed-off-by: Oleksandr Andrushchenko <[email protected]> Reviewed-by: Volodymyr Babchuk <[email protected]>
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This is a sync with android |
andr2000
pushed a commit
to andr2000/linux
that referenced
this pull request
Mar 20, 2018
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 xen-troops#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 <[email protected]>
Cc: Alan Cox <[email protected]>
Cc: [email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
andr2000
pushed a commit
to andr2000/linux
that referenced
this pull request
May 23, 2018
syzbot caught an infinite recursion in nsh_gso_segment().
Problem here is that we need to make sure the NSH header is of
reasonable length.
BUG: MAX_LOCK_DEPTH too low!
turning off the locking correctness validator.
depth: 48 max: 48!
48 locks held by syz-executor0/10189:
#0: (ptrval) (rcu_read_lock_bh){....}, at: __dev_queue_xmit+0x30f/0x34c0 net/core/dev.c:3517
#1: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
#1: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
#2: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
#2: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
#3: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
#3: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
xen-troops#4: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#4: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
xen-troops#5: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#5: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
xen-troops#6: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#6: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
xen-troops#7: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#7: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
xen-troops#8: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#8: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
xen-troops#9: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#9: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
xen-troops#10: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#10: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
xen-troops#11: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#11: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
xen-troops#12: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#12: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
xen-troops#13: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#13: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
xen-troops#14: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#14: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
xen-troops#15: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#15: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
xen-troops#16: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#16: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
xen-troops#17: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#17: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
xen-troops#18: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#18: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
xen-troops#19: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#19: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
xen-troops#20: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#20: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
xen-troops#21: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#21: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
xen-troops#22: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#22: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
xen-troops#23: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#23: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
xen-troops#24: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#24: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
xen-troops#25: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#25: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
xen-troops#26: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#26: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
xen-troops#27: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#27: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
xen-troops#28: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#28: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
xen-troops#29: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#29: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
xen-troops#30: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#30: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
xen-troops#31: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#31: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
dccp_close: ABORT with 65423 bytes unread
xen-troops#32: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#32: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
xen-troops#33: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#33: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
xen-troops#34: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#34: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
xen-troops#35: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#35: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
xen-troops#36: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#36: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
xen-troops#37: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#37: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
xen-troops#38: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#38: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
xen-troops#39: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#39: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
xen-troops#40: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#40: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
xen-troops#41: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#41: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
xen-troops#42: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#42: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
xen-troops#43: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#43: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
xen-troops#44: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#44: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
xen-troops#45: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#45: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
xen-troops#46: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#46: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
xen-troops#47: (ptrval) (rcu_read_lock){....}, at: __skb_pull include/linux/skbuff.h:2080 [inline]
xen-troops#47: (ptrval) (rcu_read_lock){....}, at: skb_mac_gso_segment+0x221/0x720 net/core/dev.c:2787
INFO: lockdep is turned off.
CPU: 1 PID: 10189 Comm: syz-executor0 Not tainted 4.17.0-rc2+ xen-troops#26
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1b9/0x294 lib/dump_stack.c:113
__lock_acquire+0x1788/0x5140 kernel/locking/lockdep.c:3449
lock_acquire+0x1dc/0x520 kernel/locking/lockdep.c:3920
rcu_lock_acquire include/linux/rcupdate.h:246 [inline]
rcu_read_lock include/linux/rcupdate.h:632 [inline]
skb_mac_gso_segment+0x25b/0x720 net/core/dev.c:2789
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
nsh_gso_segment+0x405/0xb60 net/nsh/nsh.c:107
skb_mac_gso_segment+0x3ad/0x720 net/core/dev.c:2792
__skb_gso_segment+0x3bb/0x870 net/core/dev.c:2865
skb_gso_segment include/linux/netdevice.h:4025 [inline]
validate_xmit_skb+0x54d/0xd90 net/core/dev.c:3118
validate_xmit_skb_list+0xbf/0x120 net/core/dev.c:3168
sch_direct_xmit+0x354/0x11e0 net/sched/sch_generic.c:312
qdisc_restart net/sched/sch_generic.c:399 [inline]
__qdisc_run+0x741/0x1af0 net/sched/sch_generic.c:410
__dev_xmit_skb net/core/dev.c:3243 [inline]
__dev_queue_xmit+0x28ea/0x34c0 net/core/dev.c:3551
dev_queue_xmit+0x17/0x20 net/core/dev.c:3616
packet_snd net/packet/af_packet.c:2951 [inline]
packet_sendmsg+0x40f8/0x6070 net/packet/af_packet.c:2976
sock_sendmsg_nosec net/socket.c:629 [inline]
sock_sendmsg+0xd5/0x120 net/socket.c:639
__sys_sendto+0x3d7/0x670 net/socket.c:1789
__do_sys_sendto net/socket.c:1801 [inline]
__se_sys_sendto net/socket.c:1797 [inline]
__x64_sys_sendto+0xe1/0x1a0 net/socket.c:1797
do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
entry_SYSCALL_64_after_hwframe+0x49/0xbe
Fixes: c411ed8 ("nsh: add GSO support")
Signed-off-by: Eric Dumazet <[email protected]>
Cc: Jiri Benc <[email protected]>
Reported-by: syzbot <[email protected]>
Acked-by: Jiri Benc <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
andr2000
pushed a commit
to andr2000/linux
that referenced
this pull request
Nov 27, 2018
Increase kasan instrumented kernel stack size from 32k to 64k. Other architectures seems to get away with just doubling kernel stack size under kasan, but on s390 this appears to be not enough due to bigger frame size. The particular pain point is kasan inlined checks (CONFIG_KASAN_INLINE vs CONFIG_KASAN_OUTLINE). With inlined checks one particular case hitting stack overflow is fs sync on xfs filesystem: #0 [9a0681e8] 704 bytes check_usage at 34b1fc #1 [9a0684a8] 432 bytes check_usage at 34c710 #2 [9a068658] 1048 bytes validate_chain at 35044a #3 [9a068a70] 312 bytes __lock_acquire at 3559fe xen-troops#4 [9a068ba8] 440 bytes lock_acquire at 3576ee xen-troops#5 [9a068d60] 104 bytes _raw_spin_lock at 21b44e0 xen-troops#6 [9a068dc8] 1992 bytes enqueue_entity at 2dbf72 xen-troops#7 [9a069590] 1496 bytes enqueue_task_fair at 2df5f0 xen-troops#8 [9a069b68] 64 bytes ttwu_do_activate at 28f438 xen-troops#9 [9a069ba8] 552 bytes try_to_wake_up at 298c4c xen-troops#10 [9a069dd0] 168 bytes wake_up_worker at 23f97c xen-troops#11 [9a069e78] 200 bytes insert_work at 23fc2e xen-troops#12 [9a069f40] 648 bytes __queue_work at 2487c0 xen-troops#13 [9a06a1c8] 200 bytes __queue_delayed_work at 24db28 xen-troops#14 [9a06a290] 248 bytes mod_delayed_work_on at 24de84 xen-troops#15 [9a06a388] 24 bytes kblockd_mod_delayed_work_on at 153e2a0 xen-troops#16 [9a06a3a0] 288 bytes __blk_mq_delay_run_hw_queue at 158168c xen-troops#17 [9a06a4c0] 192 bytes blk_mq_run_hw_queue at 1581a3c xen-troops#18 [9a06a580] 184 bytes blk_mq_sched_insert_requests at 15a2192 xen-troops#19 [9a06a638] 1024 bytes blk_mq_flush_plug_list at 1590f3a xen-troops#20 [9a06aa38] 704 bytes blk_flush_plug_list at 1555028 xen-troops#21 [9a06acf8] 320 bytes schedule at 219e476 xen-troops#22 [9a06ae38] 760 bytes schedule_timeout at 21b0aac xen-troops#23 [9a06b130] 408 bytes wait_for_common at 21a1706 xen-troops#24 [9a06b2c8] 360 bytes xfs_buf_iowait at fa1540 xen-troops#25 [9a06b430] 256 bytes __xfs_buf_submit at fadae6 xen-troops#26 [9a06b530] 264 bytes xfs_buf_read_map at fae3f6 xen-troops#27 [9a06b638] 656 bytes xfs_trans_read_buf_map at 10ac9a8 xen-troops#28 [9a06b8c8] 304 bytes xfs_btree_kill_root at e72426 xen-troops#29 [9a06b9f8] 288 bytes xfs_btree_lookup_get_block at e7bc5e xen-troops#30 [9a06bb18] 624 bytes xfs_btree_lookup at e7e1a6 xen-troops#31 [9a06bd88] 2664 bytes xfs_alloc_ag_vextent_near at dfa070 xen-troops#32 [9a06c7f0] 144 bytes xfs_alloc_ag_vextent at dff3ca xen-troops#33 [9a06c880] 1128 bytes xfs_alloc_vextent at e05fce xen-troops#34 [9a06cce8] 584 bytes xfs_bmap_btalloc at e58342 xen-troops#35 [9a06cf30] 1336 bytes xfs_bmapi_write at e618de xen-troops#36 [9a06d468] 776 bytes xfs_iomap_write_allocate at ff678e xen-troops#37 [9a06d770] 720 bytes xfs_map_blocks at f82af8 xen-troops#38 [9a06da40] 928 bytes xfs_writepage_map at f83cd6 xen-troops#39 [9a06dde0] 320 bytes xfs_do_writepage at f85872 xen-troops#40 [9a06df20] 1320 bytes write_cache_pages at 73dfe8 xen-troops#41 [9a06e448] 208 bytes xfs_vm_writepages at f7f892 xen-troops#42 [9a06e518] 88 bytes do_writepages at 73fe6a xen-troops#43 [9a06e570] 872 bytes __writeback_single_inode at a20cb6 xen-troops#44 [9a06e8d8] 664 bytes writeback_sb_inodes at a23be2 xen-troops#45 [9a06eb70] 296 bytes __writeback_inodes_wb at a242e0 xen-troops#46 [9a06ec98] 928 bytes wb_writeback at a2500e xen-troops#47 [9a06f038] 848 bytes wb_do_writeback at a260ae xen-troops#48 [9a06f388] 536 bytes wb_workfn at a28228 xen-troops#49 [9a06f5a0] 1088 bytes process_one_work at 24a234 xen-troops#50 [9a06f9e0] 1120 bytes worker_thread at 24ba26 xen-troops#51 [9a06fe40] 104 bytes kthread at 26545a xen-troops#52 [9a06fea8] kernel_thread_starter at 21b6b62 To be able to increase the stack size to 64k reuse LLILL instruction in __switch_to function to load 64k - STACK_FRAME_OVERHEAD - __PT_SIZE (65192) value as unsigned. Reported-by: Benjamin Block <[email protected]> Reviewed-by: Heiko Carstens <[email protected]> Signed-off-by: Vasily Gorbik <[email protected]> Signed-off-by: Martin Schwidefsky <[email protected]>
arminn
pushed a commit
to arminn/linux
that referenced
this pull request
Aug 9, 2021
[ Upstream commit b5befe8 ] An srcu_struct structure that is initialized before rcu_init_geometry() will have its srcu_node hierarchy based on CONFIG_NR_CPUS. Once rcu_init_geometry() is called, this hierarchy is compressed as needed for the actual maximum number of CPUs for this system. Later on, that srcu_struct structure is confused, sometimes referring to its initial CONFIG_NR_CPUS-based hierarchy, and sometimes instead to the new num_possible_cpus() hierarchy. For example, each of its ->mynode fields continues to reference the original leaf rcu_node structures, some of which might no longer exist. On the other hand, srcu_for_each_node_breadth_first() traverses to the new node hierarchy. There are at least two bad possible outcomes to this: 1) a) A callback enqueued early on an srcu_data structure (call it *sdp) is recorded pending on sdp->mynode->srcu_data_have_cbs in srcu_funnel_gp_start() with sdp->mynode pointing to a deep leaf (say 3 levels). b) The grace period ends after rcu_init_geometry() shrinks the nodes level to a single one. srcu_gp_end() walks through the new srcu_node hierarchy without ever reaching the old leaves so the callback is never executed. This is easily reproduced on an 8 CPUs machine with CONFIG_NR_CPUS >= 32 and "rcupdate.rcu_self_test=1". The srcu_barrier() after early tests verification never completes and the boot hangs: [ 5413.141029] INFO: task swapper/0:1 blocked for more than 4915 seconds. [ 5413.147564] Not tainted 5.12.0-rc4+ xen-troops#28 [ 5413.151927] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 5413.159753] task:swapper/0 state:D stack: 0 pid: 1 ppid: 0 flags:0x00004000 [ 5413.168099] Call Trace: [ 5413.170555] __schedule+0x36c/0x930 [ 5413.174057] ? wait_for_completion+0x88/0x110 [ 5413.178423] schedule+0x46/0xf0 [ 5413.181575] schedule_timeout+0x284/0x380 [ 5413.185591] ? wait_for_completion+0x88/0x110 [ 5413.189957] ? mark_held_locks+0x61/0x80 [ 5413.193882] ? mark_held_locks+0x61/0x80 [ 5413.197809] ? _raw_spin_unlock_irq+0x24/0x50 [ 5413.202173] ? wait_for_completion+0x88/0x110 [ 5413.206535] wait_for_completion+0xb4/0x110 [ 5413.210724] ? srcu_torture_stats_print+0x110/0x110 [ 5413.215610] srcu_barrier+0x187/0x200 [ 5413.219277] ? rcu_tasks_verify_self_tests+0x50/0x50 [ 5413.224244] ? rdinit_setup+0x2b/0x2b [ 5413.227907] rcu_verify_early_boot_tests+0x2d/0x40 [ 5413.232700] do_one_initcall+0x63/0x310 [ 5413.236541] ? rdinit_setup+0x2b/0x2b [ 5413.240207] ? rcu_read_lock_sched_held+0x52/0x80 [ 5413.244912] kernel_init_freeable+0x253/0x28f [ 5413.249273] ? rest_init+0x250/0x250 [ 5413.252846] kernel_init+0xa/0x110 [ 5413.256257] ret_from_fork+0x22/0x30 2) An srcu_struct structure that is initialized before rcu_init_geometry() and used afterward will always have stale rdp->mynode references, resulting in callbacks to be missed in srcu_gp_end(), just like in the previous scenario. This commit therefore causes init_srcu_struct_nodes to initialize the geometry, if needed. This ensures that the srcu_node hierarchy is properly built and distributed from the get-go. Suggested-by: Paul E. McKenney <[email protected]> Signed-off-by: Frederic Weisbecker <[email protected]> Cc: Boqun Feng <[email protected]> Cc: Lai Jiangshan <[email protected]> Cc: Neeraj Upadhyay <[email protected]> Cc: Josh Triplett <[email protected]> Cc: Joel Fernandes <[email protected]> Cc: Uladzislau Rezki <[email protected]> Signed-off-by: Paul E. McKenney <[email protected]> Signed-off-by: Sasha Levin <[email protected]>
otyshchenko1
pushed a commit
to otyshchenko1/linux
that referenced
this pull request
Oct 5, 2022
The assumption in __disable_kprobe() is wrong, and it could try to disarm
an already disarmed kprobe and fire the WARN_ONCE() below. [0] We can
easily reproduce this issue.
1. Write 0 to /sys/kernel/debug/kprobes/enabled.
# echo 0 > /sys/kernel/debug/kprobes/enabled
2. Run execsnoop. At this time, one kprobe is disabled.
# /usr/share/bcc/tools/execsnoop &
[1] 2460
PCOMM PID PPID RET ARGS
# cat /sys/kernel/debug/kprobes/list
ffffffff91345650 r __x64_sys_execve+0x0 [FTRACE]
ffffffff91345650 k __x64_sys_execve+0x0 [DISABLED][FTRACE]
3. Write 1 to /sys/kernel/debug/kprobes/enabled, which changes
kprobes_all_disarmed to false but does not arm the disabled kprobe.
# echo 1 > /sys/kernel/debug/kprobes/enabled
# cat /sys/kernel/debug/kprobes/list
ffffffff91345650 r __x64_sys_execve+0x0 [FTRACE]
ffffffff91345650 k __x64_sys_execve+0x0 [DISABLED][FTRACE]
4. Kill execsnoop, when __disable_kprobe() calls disarm_kprobe() for the
disabled kprobe and hits the WARN_ONCE() in __disarm_kprobe_ftrace().
# fg
/usr/share/bcc/tools/execsnoop
^C
Actually, WARN_ONCE() is fired twice, and __unregister_kprobe_top() misses
some cleanups and leaves the aggregated kprobe in the hash table. Then,
__unregister_trace_kprobe() initialises tk->rp.kp.list and creates an
infinite loop like this.
aggregated kprobe.list -> kprobe.list -.
^ |
'.__.'
In this situation, these commands fall into the infinite loop and result
in RCU stall or soft lockup.
cat /sys/kernel/debug/kprobes/list : show_kprobe_addr() enters into the
infinite loop with RCU.
/usr/share/bcc/tools/execsnoop : warn_kprobe_rereg() holds kprobe_mutex,
and __get_valid_kprobe() is stuck in
the loop.
To avoid the issue, make sure we don't call disarm_kprobe() for disabled
kprobes.
[0]
Failed to disarm kprobe-ftrace at __x64_sys_execve+0x0/0x40 (error -2)
WARNING: CPU: 6 PID: 2460 at kernel/kprobes.c:1130 __disarm_kprobe_ftrace.isra.19 (kernel/kprobes.c:1129)
Modules linked in: ena
CPU: 6 PID: 2460 Comm: execsnoop Not tainted 5.19.0+ xen-troops#28
Hardware name: Amazon EC2 c5.2xlarge/, BIOS 1.0 10/16/2017
RIP: 0010:__disarm_kprobe_ftrace.isra.19 (kernel/kprobes.c:1129)
Code: 24 8b 02 eb c1 80 3d c4 83 f2 01 00 75 d4 48 8b 75 00 89 c2 48 c7 c7 90 fa 0f 92 89 04 24 c6 05 ab 83 01 e8 e4 94 f0 ff <0f> 0b 8b 04 24 eb b1 89 c6 48 c7 c7 60 fa 0f 92 89 04 24 e8 cc 94
RSP: 0018:ffff9e6ec154bd98 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffffffff930f7b00 RCX: 0000000000000001
RDX: 0000000080000001 RSI: ffffffff921461c5 RDI: 00000000ffffffff
RBP: ffff89c504286da8 R08: 0000000000000000 R09: c0000000fffeffff
R10: 0000000000000000 R11: ffff9e6ec154bc28 R12: ffff89c502394e40
R13: ffff89c502394c00 R14: ffff9e6ec154bc00 R15: 0000000000000000
FS: 00007fe800398740(0000) GS:ffff89c812d80000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c00057f010 CR3: 0000000103b54006 CR4: 00000000007706e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
<TASK>
__disable_kprobe (kernel/kprobes.c:1716)
disable_kprobe (kernel/kprobes.c:2392)
__disable_trace_kprobe (kernel/trace/trace_kprobe.c:340)
disable_trace_kprobe (kernel/trace/trace_kprobe.c:429)
perf_trace_event_unreg.isra.2 (./include/linux/tracepoint.h:93 kernel/trace/trace_event_perf.c:168)
perf_kprobe_destroy (kernel/trace/trace_event_perf.c:295)
_free_event (kernel/events/core.c:4971)
perf_event_release_kernel (kernel/events/core.c:5176)
perf_release (kernel/events/core.c:5186)
__fput (fs/file_table.c:321)
task_work_run (./include/linux/sched.h:2056 (discriminator 1) kernel/task_work.c:179 (discriminator 1))
exit_to_user_mode_prepare (./include/linux/resume_user_mode.h:49 kernel/entry/common.c:169 kernel/entry/common.c:201)
syscall_exit_to_user_mode (./arch/x86/include/asm/jump_label.h:55 ./arch/x86/include/asm/nospec-branch.h:384 ./arch/x86/include/asm/entry-common.h:94 kernel/entry/common.c:133 kernel/entry/common.c:296)
do_syscall_64 (arch/x86/entry/common.c:87)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120)
RIP: 0033:0x7fe7ff210654
Code: 15 79 89 20 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb be 0f 1f 00 8b 05 9a cd 20 00 48 63 ff 85 c0 75 11 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 3a f3 c3 48 83 ec 18 48 89 7c 24 08 e8 34 fc
RSP: 002b:00007ffdbd1d3538 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000008 RCX: 00007fe7ff210654
RDX: 0000000000000000 RSI: 0000000000002401 RDI: 0000000000000008
RBP: 0000000000000000 R08: 94ae31d6fda838a4 R0900007fe8001c9d30
R10: 00007ffdbd1d34b0 R11: 0000000000000246 R12: 00007ffdbd1d3600
R13: 0000000000000000 R14: fffffffffffffffc R15: 00007ffdbd1d3560
</TASK>
Link: https://lkml.kernel.org/r/[email protected]
Fixes: 69d54b9 ("kprobes: makes kprobes/enabled works correctly for optimized kprobes.")
Signed-off-by: Kuniyuki Iwashima <[email protected]>
Reported-by: Ayushman Dutta <[email protected]>
Cc: "Naveen N. Rao" <[email protected]>
Cc: Anil S Keshavamurthy <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Cc: Wang Nan <[email protected]>
Cc: Kuniyuki Iwashima <[email protected]>
Cc: Kuniyuki Iwashima <[email protected]>
Cc: Ayushman Dutta <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
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Move from a single vblank timer which handles both
vblank emulation and page flip time-outs to a dedicated
vblank timer per DRM driver and page flip time-out
timer per CRTC.
Signed-off-by: Oleksandr Andrushchenko [email protected]
Reviewed-by: Volodymyr Babchuk [email protected]