* WARNING in __might_sleep (2) @ 2018-12-29 0:41 syzbot 2018-12-29 11:48 ` [PATCH] tty/n_hdlc: fix sleep in !TASK_RUNNING state warning Tetsuo Handa 0 siblings, 1 reply; 13+ messages in thread From: syzbot @ 2018-12-29 0:41 UTC (permalink / raw) To: gregkh, jslaby, linux-kernel, syzkaller-bugs Hello, syzbot found the following crash on: HEAD commit: 8fe28cb58bcb Linux 4.20 git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=16211a3b400000 kernel config: https://syzkaller.appspot.com/x/.config?x=7d581260bae0899a dashboard link: https://syzkaller.appspot.com/bug?extid=c244af085a0159d22879 compiler: gcc (GCC) 8.0.1 20180413 (experimental) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1617cd8b400000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11f5089b400000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+c244af085a0159d22879@syzkaller.appspotmail.com audit: type=1800 audit(1545700018.193:29): pid=7508 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="startpar" name="rc.local" dev="sda1" ino=2432 res=0 ------------[ cut here ]------------ do not call blocking ops when !TASK_RUNNING; state=1 set at [<000000004df58f46>] n_hdlc_tty_read+0x301/0x7f0 drivers/tty/n_hdlc.c:589 WARNING: CPU: 0 PID: 7659 at kernel/sched/core.c:6099 __might_sleep+0x13d/0x190 kernel/sched/core.c:6094 Kernel panic - not syncing: panic_on_warn set ... CPU: 0 PID: 7659 Comm: syz-executor111 Not tainted 4.20.0 #387 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+0x1d3/0x2c6 lib/dump_stack.c:113 panic+0x2ad/0x55c kernel/panic.c:188 __warn.cold.8+0x20/0x45 kernel/panic.c:540 report_bug+0x254/0x2d0 lib/bug.c:186 fixup_bug arch/x86/kernel/traps.c:178 [inline] do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:271 do_invalid_op+0x36/0x40 arch/x86/kernel/traps.c:290 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:973 RIP: 0010:__might_sleep+0x13d/0x190 kernel/sched/core.c:6094 Code: 65 48 8b 1c 25 40 ee 01 00 48 8d 7b 10 48 89 fe 48 c1 ee 03 80 3c 06 00 75 2b 48 8b 73 10 48 c7 c7 40 e0 2a 88 e8 43 27 f3 ff <0f> 0b e9 43 ff ff ff e8 f7 7c 6c 00 e9 26 ff ff ff e8 ed 7c 6c 00 RSP: 0018:ffff8881b8db7948 EFLAGS: 00010286 RAX: 0000000000000000 RBX: ffff8881b8cae6c0 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff8164e045 RDI: 0000000000000005 RBP: ffff8881b8db7978 R08: ffff8881b8cae6c0 R09: 0000000000000007 R10: 0000000000000000 R11: ffff8881b8cae6c0 R12: ffffffff8860b220 R13: 0000000000000019 R14: 0000000000000000 R15: ffff8881b8cae6c0 __might_fault+0xc6/0x1e0 mm/memory.c:4357 _copy_to_user+0x30/0x110 lib/usercopy.c:25 copy_to_user include/linux/uaccess.h:155 [inline] n_hdlc_tty_read+0x5c1/0x7f0 drivers/tty/n_hdlc.c:600 tty_read+0x194/0x2a0 drivers/tty/tty_io.c:866 __vfs_read+0x117/0x9b0 fs/read_write.c:416 vfs_read+0x17f/0x3c0 fs/read_write.c:452 ksys_read+0x101/0x260 fs/read_write.c:578 __do_sys_read fs/read_write.c:588 [inline] __se_sys_read fs/read_write.c:586 [inline] __x64_sys_read+0x73/0xb0 fs/read_write.c:586 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x440099 Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ffeeb4e9ec8 EFLAGS: 00000207 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440099 RDX: 0000000000000057 RSI: 0000000020000080 RDI: 0000000000000003 RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8 R10: 00000000004002c8 R11: 0000000000000207 R12: 0000000000401920 R13: 00000000004019b0 R14: 0000000000000000 R15: 0000000000000000 Kernel Offset: disabled Rebooting in 86400 seconds.. --- This bug is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this bug report. See: https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with syzbot. syzbot can test patches for this bug, for details see: https://goo.gl/tpsmEJ#testing-patches ^ permalink raw reply [flat|nested] 13+ messages in thread
* [PATCH] tty/n_hdlc: fix sleep in !TASK_RUNNING state warning 2018-12-29 0:41 WARNING in __might_sleep (2) syzbot @ 2018-12-29 11:48 ` Tetsuo Handa 2019-01-01 3:13 ` Paul Fulghum [not found] ` <FEBFE826-8D27-4A0B-86A5-BA559921CADC@microgate.com> 0 siblings, 2 replies; 13+ messages in thread From: Tetsuo Handa @ 2018-12-29 11:48 UTC (permalink / raw) To: Paul Fulghum, Arnd Bergmann, Alan Cox Cc: syzbot, gregkh, jslaby, linux-kernel, syzkaller-bugs syzbot is hitting __might_sleep() warning [1], for commit 1035b63d3c6fc34a ("n_hdlc: fix read and write locking") changed to set TASK_INTERRUPTIBLE state before calling copy_to_user(). Let's set TASK_INTERRUPTIBLE state immediately before calling schedule(). [1] https://syzkaller.appspot.com/bug?id=17d5de7f1fcab794cb8c40032f893f52de899324 Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reported-by: syzbot <syzbot+c244af085a0159d22879@syzkaller.appspotmail.com> Cc: Paul Fulghum <paulkf@microgate.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> --- drivers/tty/n_hdlc.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/drivers/tty/n_hdlc.c b/drivers/tty/n_hdlc.c index dabb391..7835489 100644 --- a/drivers/tty/n_hdlc.c +++ b/drivers/tty/n_hdlc.c @@ -589,8 +589,6 @@ static ssize_t n_hdlc_tty_read(struct tty_struct *tty, struct file *file, if (tty_hung_up_p(file)) break; - set_current_state(TASK_INTERRUPTIBLE); - rbuf = n_hdlc_buf_get(&n_hdlc->rx_buf_list); if (rbuf) { if (rbuf->count > nr) { @@ -617,6 +615,7 @@ static ssize_t n_hdlc_tty_read(struct tty_struct *tty, struct file *file, break; } + set_current_state(TASK_INTERRUPTIBLE); schedule(); if (signal_pending(current)) { @@ -673,8 +672,6 @@ static ssize_t n_hdlc_tty_write(struct tty_struct *tty, struct file *file, add_wait_queue(&tty->write_wait, &wait); for (;;) { - set_current_state(TASK_INTERRUPTIBLE); - tbuf = n_hdlc_buf_get(&n_hdlc->tx_free_buf_list); if (tbuf) break; @@ -683,6 +680,8 @@ static ssize_t n_hdlc_tty_write(struct tty_struct *tty, struct file *file, error = -EAGAIN; break; } + + set_current_state(TASK_INTERRUPTIBLE); schedule(); n_hdlc = tty2n_hdlc (tty); -- 1.8.3.1 ^ permalink raw reply related [flat|nested] 13+ messages in thread
* Re: [PATCH] tty/n_hdlc: fix sleep in !TASK_RUNNING state warning 2018-12-29 11:48 ` [PATCH] tty/n_hdlc: fix sleep in !TASK_RUNNING state warning Tetsuo Handa @ 2019-01-01 3:13 ` Paul Fulghum 2019-01-01 20:28 ` [PATCH] tty/n_hdlc: fix __might_sleep warning Paul Fulghum [not found] ` <FEBFE826-8D27-4A0B-86A5-BA559921CADC@microgate.com> 1 sibling, 1 reply; 13+ messages in thread From: Paul Fulghum @ 2019-01-01 3:13 UTC (permalink / raw) To: Tetsuo Handa Cc: Arnd Bergmann, Alan Cox, syzbot, gregkh, jslaby, linux-kernel, syzkaller-bugs On Dec 31, 2018, at 7:11 PM, Paul Fulghum <paulkf@microgate.com> wrote: NAK to this patch. It causes lost wakeups in both read and write paths. The write path does not need changing. The read path can be fixed by setting current to TASK_RUNNING at the top of the if (rbuf) block so the warning is not triggered by copy_to_user(). If this block runs the condition is satisfied and it breaks out of the polling loop where it is already being set to TASK_RUNNING and removed from the wait queue. This particular path just needs to account for the copy_to_user which occurs before breaking out. I’ll make a patch to do this when I have the ability to test it in a day or two. > On Dec 29, 2018, at 3:48 AM, Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> wrote: > > syzbot is hitting __might_sleep() warning [1], for commit 1035b63d3c6fc34a > ("n_hdlc: fix read and write locking") changed to set TASK_INTERRUPTIBLE > state before calling copy_to_user(). Let's set TASK_INTERRUPTIBLE state > immediately before calling schedule(). > > [1] https://syzkaller.appspot.com/bug?id=17d5de7f1fcab794cb8c40032f893f52de899324 > > Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> > Reported-by: syzbot <syzbot+c244af085a0159d22879@syzkaller.appspotmail.com> > Cc: Paul Fulghum <paulkf@microgate.com> > Cc: Arnd Bergmann <arnd@arndb.de> > Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> > --- > drivers/tty/n_hdlc.c | 7 +++---- > 1 file changed, 3 insertions(+), 4 deletions(-) > > diff --git a/drivers/tty/n_hdlc.c b/drivers/tty/n_hdlc.c > index dabb391..7835489 100644 > --- a/drivers/tty/n_hdlc.c > +++ b/drivers/tty/n_hdlc.c > @@ -589,8 +589,6 @@ static ssize_t n_hdlc_tty_read(struct tty_struct *tty, struct file *file, > if (tty_hung_up_p(file)) > break; > > - set_current_state(TASK_INTERRUPTIBLE); > - > rbuf = n_hdlc_buf_get(&n_hdlc->rx_buf_list); > if (rbuf) { > if (rbuf->count > nr) { > @@ -617,6 +615,7 @@ static ssize_t n_hdlc_tty_read(struct tty_struct *tty, struct file *file, > break; > } > > + set_current_state(TASK_INTERRUPTIBLE); > schedule(); > > if (signal_pending(current)) { > @@ -673,8 +672,6 @@ static ssize_t n_hdlc_tty_write(struct tty_struct *tty, struct file *file, > add_wait_queue(&tty->write_wait, &wait); > > for (;;) { > - set_current_state(TASK_INTERRUPTIBLE); > - > tbuf = n_hdlc_buf_get(&n_hdlc->tx_free_buf_list); > if (tbuf) > break; > @@ -683,6 +680,8 @@ static ssize_t n_hdlc_tty_write(struct tty_struct *tty, struct file *file, > error = -EAGAIN; > break; > } > + > + set_current_state(TASK_INTERRUPTIBLE); > schedule(); > > n_hdlc = tty2n_hdlc (tty); > -- > 1.8.3.1 > > -- Paul Fulghum MicroGate Systems, Ltd. =Customer Driven, by Design= (512) 345-7791 x102 (Voice) (512) 343-9046 (Fax) Central Time Zone (GMT -5h) www.microgate.com ^ permalink raw reply [flat|nested] 13+ messages in thread
* [PATCH] tty/n_hdlc: fix __might_sleep warning 2019-01-01 3:13 ` Paul Fulghum @ 2019-01-01 20:28 ` Paul Fulghum 2019-01-10 11:38 ` Tetsuo Handa 0 siblings, 1 reply; 13+ messages in thread From: Paul Fulghum @ 2019-01-01 20:28 UTC (permalink / raw) To: linux-kernel@vger.kernel.org Mailing List Cc: Greg Kroah-Hartman, Tetsuo Handa, Arnd Bergmann, Alan Cox, syzbot, jslaby, syzkaller-bugs Fix __might_sleep warning in tty/n_hdlc.c read due to copy_to_user call while current is TASK_INTERRUPTIBLE. This is a false positive since the code path does not depend on current state remaining TASK_INTERRUPTIBLE. The loop breaks out and sets TASK_RUNNING after calling copy_to_user. This patch supresses the warning by setting TASK_RUNNING before calling copy_to_user. [1] https://syzkaller.appspot.com/bug?id=17d5de7f1fcab794cb8c40032f893f52de899324 Signed-off-by: Paul Fulghum <paulkf@microgate.com> Reported-by: syzbot <syzbot+c244af085a0159d22879@syzkaller.appspotmail.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> — --- a/drivers/tty/n_hdlc.c 2018-12-23 15:55:59.000000000 -0800 +++ b/drivers/tty/n_hdlc.c 2019-01-01 11:44:47.148153954 -0800 @@ -597,6 +597,7 @@ static ssize_t n_hdlc_tty_read(struct tt /* too large for caller's buffer */ ret = -EOVERFLOW; } else { + __set_current_state(TASK_RUNNING); if (copy_to_user(buf, rbuf->buf, rbuf->count)) ret = -EFAULT; else ^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH] tty/n_hdlc: fix __might_sleep warning 2019-01-01 20:28 ` [PATCH] tty/n_hdlc: fix __might_sleep warning Paul Fulghum @ 2019-01-10 11:38 ` Tetsuo Handa 2019-01-10 12:25 ` Arnd Bergmann 0 siblings, 1 reply; 13+ messages in thread From: Tetsuo Handa @ 2019-01-10 11:38 UTC (permalink / raw) To: Greg Kroah-Hartman, jslaby Cc: Paul Fulghum, linux-kernel@vger.kernel.org Mailing List, Arnd Bergmann, Alan Cox, syzbot, syzkaller-bugs Hello, Greg. We attempted a cleanup but we failed. Thus, will you apply this patch for now? On 2019/01/02 5:28, Paul Fulghum wrote: > Fix __might_sleep warning in tty/n_hdlc.c read due to copy_to_user call while current is TASK_INTERRUPTIBLE. > This is a false positive since the code path does not depend on current state remaining TASK_INTERRUPTIBLE. > The loop breaks out and sets TASK_RUNNING after calling copy_to_user. > This patch supresses the warning by setting TASK_RUNNING before calling copy_to_user. > > [1] https://syzkaller.appspot.com/bug?id=17d5de7f1fcab794cb8c40032f893f52de899324 > > Signed-off-by: Paul Fulghum <paulkf@microgate.com> > Reported-by: syzbot <syzbot+c244af085a0159d22879@syzkaller.appspotmail.com> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> > Cc: Arnd Bergmann <arnd@arndb.de> > Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> > — > --- a/drivers/tty/n_hdlc.c 2018-12-23 15:55:59.000000000 -0800 > +++ b/drivers/tty/n_hdlc.c 2019-01-01 11:44:47.148153954 -0800 > @@ -597,6 +597,7 @@ static ssize_t n_hdlc_tty_read(struct tt > /* too large for caller's buffer */ > ret = -EOVERFLOW; > } else { > + __set_current_state(TASK_RUNNING); > if (copy_to_user(buf, rbuf->buf, rbuf->count)) > ret = -EFAULT; > else ^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH] tty/n_hdlc: fix __might_sleep warning 2019-01-10 11:38 ` Tetsuo Handa @ 2019-01-10 12:25 ` Arnd Bergmann 0 siblings, 0 replies; 13+ messages in thread From: Arnd Bergmann @ 2019-01-10 12:25 UTC (permalink / raw) To: Tetsuo Handa Cc: Greg Kroah-Hartman, Jiri Slaby, Paul Fulghum, linux-kernel@vger.kernel.org Mailing List, Alan Cox, syzbot, syzkaller-bugs On Thu, Jan 10, 2019 at 12:39 PM Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> wrote: > On 2019/01/02 5:28, Paul Fulghum wrote: > > Fix __might_sleep warning in tty/n_hdlc.c read due to copy_to_user call while current is TASK_INTERRUPTIBLE. > > This is a false positive since the code path does not depend on current state remaining TASK_INTERRUPTIBLE. > > The loop breaks out and sets TASK_RUNNING after calling copy_to_user. > > This patch supresses the warning by setting TASK_RUNNING before calling copy_to_user. > > > > [1] https://syzkaller.appspot.com/bug?id=17d5de7f1fcab794cb8c40032f893f52de899324 > > > > Signed-off-by: Paul Fulghum <paulkf@microgate.com> > > Reported-by: syzbot <syzbot+c244af085a0159d22879@syzkaller.appspotmail.com> > > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > > Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> > > Cc: Arnd Bergmann <arnd@arndb.de> > > Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> This version looks good to me. Acked-by: Arnd Bergmann <arnd@arndb.de> Arnd ^ permalink raw reply [flat|nested] 13+ messages in thread
[parent not found: <FEBFE826-8D27-4A0B-86A5-BA559921CADC@microgate.com>]
* Re: [PATCH] tty/n_hdlc: fix sleep in !TASK_RUNNING state warning [not found] ` <FEBFE826-8D27-4A0B-86A5-BA559921CADC@microgate.com> @ 2019-01-02 15:04 ` Tetsuo Handa 2019-01-02 20:55 ` Paul Fulghum 2019-01-03 9:09 ` Jiri Slaby 0 siblings, 2 replies; 13+ messages in thread From: Tetsuo Handa @ 2019-01-02 15:04 UTC (permalink / raw) To: Paul Fulghum; +Cc: Arnd Bergmann, Alan Cox, gregkh, jslaby, linux-kernel On 2019/01/01 12:11, Paul Fulghum wrote: > NAK to this patch. It causes lost wakeups in both read and write paths. > > The write path does not need changing. > > The read path can be fixed by setting current to TASK_RUNNING at the top of the if (rbuf) block > so the warning is not triggered by copy_to_user(). If this block runs the condition is satisfied > and it breaks out of the polling loop where it is already being set to TASK_RUNNING and removed > from the wait queue. This particular path just needs to account for the copy_to_user which occurs > before breaking out. > > I’ll make a patch to do this when I have the ability to test it in a day or two. > OK. Then, any chance it is rewritten using wait_event_interruptible() in order to reduce lines? ( wait_event_interruptible() automatically calls might_sleep(), but is it acceptable for you? ) --- drivers/tty/n_hdlc.c | 126 ++++++++++++--------------------------------------- 1 file changed, 30 insertions(+), 96 deletions(-) diff --git a/drivers/tty/n_hdlc.c b/drivers/tty/n_hdlc.c index 8223d02..2e4ccf9 100644 --- a/drivers/tty/n_hdlc.c +++ b/drivers/tty/n_hdlc.c @@ -562,8 +562,7 @@ static ssize_t n_hdlc_tty_read(struct tty_struct *tty, struct file *file, { struct n_hdlc *n_hdlc = tty2n_hdlc(tty); int ret = 0; - struct n_hdlc_buf *rbuf; - DECLARE_WAITQUEUE(wait, current); + struct n_hdlc_buf *rbuf = NULL; if (debuglevel >= DEBUG_LEVEL_INFO) printk("%s(%d)n_hdlc_tty_read() called\n",__FILE__,__LINE__); @@ -579,58 +578,26 @@ static ssize_t n_hdlc_tty_read(struct tty_struct *tty, struct file *file, return -EFAULT; } - add_wait_queue(&tty->read_wait, &wait); - - for (;;) { - if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) { - ret = -EIO; - break; - } - if (tty_hung_up_p(file)) - break; - - set_current_state(TASK_INTERRUPTIBLE); - - rbuf = n_hdlc_buf_get(&n_hdlc->rx_buf_list); - if (rbuf) { - if (rbuf->count > nr) { - /* too large for caller's buffer */ - ret = -EOVERFLOW; - } else { - __set_current_state(TASK_RUNNING); - if (copy_to_user(buf, rbuf->buf, rbuf->count)) - ret = -EFAULT; - else - ret = rbuf->count; - } - - if (n_hdlc->rx_free_buf_list.count > - DEFAULT_RX_BUF_COUNT) - kfree(rbuf); - else - n_hdlc_buf_put(&n_hdlc->rx_free_buf_list, rbuf); - break; - } - - /* no data */ - if (tty_io_nonblock(tty, file)) { - ret = -EAGAIN; - break; - } - - schedule(); - - if (signal_pending(current)) { - ret = -EINTR; - break; - } + if (wait_event_interruptible(tty->read_wait, + (ret = -EIO, test_bit(TTY_OTHER_CLOSED, &tty->flags)) || + (ret = 0, tty_hung_up_p(file)) || + (rbuf = n_hdlc_buf_get(&n_hdlc->rx_buf_list)) != NULL || + (ret = -EAGAIN, tty_io_nonblock(tty, file)))) + return -EINTR; + if (rbuf) { + if (rbuf->count > nr) + /* too large for caller's buffer */ + ret = -EOVERFLOW; + else if (copy_to_user(buf, rbuf->buf, rbuf->count)) + ret = -EFAULT; + else + ret = rbuf->count; + if (n_hdlc->rx_free_buf_list.count > DEFAULT_RX_BUF_COUNT) + kfree(rbuf); + else + n_hdlc_buf_put(&n_hdlc->rx_free_buf_list, rbuf); } - - remove_wait_queue(&tty->read_wait, &wait); - __set_current_state(TASK_RUNNING); - return ret; - } /* end of n_hdlc_tty_read() */ /** @@ -645,21 +612,13 @@ static ssize_t n_hdlc_tty_read(struct tty_struct *tty, struct file *file, static ssize_t n_hdlc_tty_write(struct tty_struct *tty, struct file *file, const unsigned char *data, size_t count) { - struct n_hdlc *n_hdlc = tty2n_hdlc (tty); + struct n_hdlc *n_hdlc; int error = 0; - DECLARE_WAITQUEUE(wait, current); - struct n_hdlc_buf *tbuf; + struct n_hdlc_buf *tbuf = NULL; if (debuglevel >= DEBUG_LEVEL_INFO) printk("%s(%d)n_hdlc_tty_write() called count=%zd\n", __FILE__,__LINE__,count); - - /* Verify pointers */ - if (!n_hdlc) - return -EIO; - - if (n_hdlc->magic != HDLC_MAGIC) - return -EIO; /* verify frame size */ if (count > maxframe ) { @@ -670,40 +629,14 @@ static ssize_t n_hdlc_tty_write(struct tty_struct *tty, struct file *file, maxframe ); count = maxframe; } - - add_wait_queue(&tty->write_wait, &wait); - for (;;) { - set_current_state(TASK_INTERRUPTIBLE); - - tbuf = n_hdlc_buf_get(&n_hdlc->tx_free_buf_list); - if (tbuf) - break; - - if (tty_io_nonblock(tty, file)) { - error = -EAGAIN; - break; - } - schedule(); - - n_hdlc = tty2n_hdlc (tty); - if (!n_hdlc || n_hdlc->magic != HDLC_MAGIC || - tty != n_hdlc->tty) { - printk("n_hdlc_tty_write: %p invalid after wait!\n", n_hdlc); - error = -EIO; - break; - } - - if (signal_pending(current)) { - error = -EINTR; - break; - } - } - - __set_current_state(TASK_RUNNING); - remove_wait_queue(&tty->write_wait, &wait); - - if (!error) { + if (wait_event_interruptible(tty->write_wait, + (error = -EIO, n_hdlc = tty2n_hdlc(tty), /* Verify pointers */ + !n_hdlc || n_hdlc->magic != HDLC_MAGIC || tty != n_hdlc->tty) || + (tbuf = n_hdlc_buf_get(&n_hdlc->tx_free_buf_list)) != NULL || + (error = -EAGAIN, tty_io_nonblock(tty, file)))) + return -EINTR; + if (tbuf) { /* Retrieve the user's buffer */ memcpy(tbuf->buf, data, count); @@ -711,8 +644,9 @@ static ssize_t n_hdlc_tty_write(struct tty_struct *tty, struct file *file, tbuf->count = error = count; n_hdlc_buf_put(&n_hdlc->tx_buf_list,tbuf); n_hdlc_send_frames(n_hdlc,tty); + } else if (error == -EIO) { + printk("n_hdlc_tty_write: %p invalid!\n", n_hdlc); } - return error; } /* end of n_hdlc_tty_write() */ -- 1.8.3.1 ^ permalink raw reply related [flat|nested] 13+ messages in thread
* Re: [PATCH] tty/n_hdlc: fix sleep in !TASK_RUNNING state warning 2019-01-02 15:04 ` [PATCH] tty/n_hdlc: fix sleep in !TASK_RUNNING state warning Tetsuo Handa @ 2019-01-02 20:55 ` Paul Fulghum 2019-01-03 9:09 ` Jiri Slaby 1 sibling, 0 replies; 13+ messages in thread From: Paul Fulghum @ 2019-01-02 20:55 UTC (permalink / raw) To: Tetsuo Handa; +Cc: Arnd Bergmann, Alan Cox, gregkh, jslaby, linux-kernel > On Jan 2, 2019, at 7:04 AM, Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> wrote: > > On 2019/01/01 12:11, Paul Fulghum wrote: >> NAK to this patch. It causes lost wakeups in both read and write paths. >> >> The write path does not need changing. >> >> The read path can be fixed by setting current to TASK_RUNNING at the top of the if (rbuf) block >> so the warning is not triggered by copy_to_user(). If this block runs the condition is satisfied >> and it breaks out of the polling loop where it is already being set to TASK_RUNNING and removed >> from the wait queue. This particular path just needs to account for the copy_to_user which occurs >> before breaking out. >> >> I’ll make a patch to do this when I have the ability to test it in a day or two. >> > > OK. Then, any chance it is rewritten using wait_event_interruptible() in order to reduce lines? > ( wait_event_interruptible() automatically calls might_sleep(), but is it acceptable for you? ) > This looks good to me. I applied it and tested blocking (sleep/no sleep) and non-blocking (success/EAGAIN) paths for both read and write. ^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH] tty/n_hdlc: fix sleep in !TASK_RUNNING state warning 2019-01-02 15:04 ` [PATCH] tty/n_hdlc: fix sleep in !TASK_RUNNING state warning Tetsuo Handa 2019-01-02 20:55 ` Paul Fulghum @ 2019-01-03 9:09 ` Jiri Slaby 2019-01-03 11:32 ` Tetsuo Handa 1 sibling, 1 reply; 13+ messages in thread From: Jiri Slaby @ 2019-01-03 9:09 UTC (permalink / raw) To: Tetsuo Handa, Paul Fulghum; +Cc: Arnd Bergmann, gregkh, Alan Cox, linux-kernel On 02. 01. 19, 16:04, Tetsuo Handa wrote: > + if (wait_event_interruptible(tty->read_wait, > + (ret = -EIO, test_bit(TTY_OTHER_CLOSED, &tty->flags)) || > + (ret = 0, tty_hung_up_p(file)) || > + (rbuf = n_hdlc_buf_get(&n_hdlc->rx_buf_list)) != NULL || > + (ret = -EAGAIN, tty_io_nonblock(tty, file)))) > + return -EINTR; Oh, that looks really ugly. Could you move all this to a function returning a bool and taking &ret and &rbuf as parameters? > + if (rbuf) { > + if (rbuf->count > nr) > + /* too large for caller's buffer */ > + ret = -EOVERFLOW; > + else if (copy_to_user(buf, rbuf->buf, rbuf->count)) > + ret = -EFAULT; > + else > + ret = rbuf->count; > + if (n_hdlc->rx_free_buf_list.count > DEFAULT_RX_BUF_COUNT) > + kfree(rbuf); > + else > + n_hdlc_buf_put(&n_hdlc->rx_free_buf_list, rbuf); > } > - > - remove_wait_queue(&tty->read_wait, &wait); > - __set_current_state(TASK_RUNNING); > - > return ret; > - > } /* end of n_hdlc_tty_read() */ > > /** > @@ -645,21 +612,13 @@ static ssize_t n_hdlc_tty_read(struct tty_struct *tty, struct file *file, > static ssize_t n_hdlc_tty_write(struct tty_struct *tty, struct file *file, > const unsigned char *data, size_t count) > { > - struct n_hdlc *n_hdlc = tty2n_hdlc (tty); > + struct n_hdlc *n_hdlc; > int error = 0; > - DECLARE_WAITQUEUE(wait, current); > - struct n_hdlc_buf *tbuf; > + struct n_hdlc_buf *tbuf = NULL; > > if (debuglevel >= DEBUG_LEVEL_INFO) > printk("%s(%d)n_hdlc_tty_write() called count=%zd\n", > __FILE__,__LINE__,count); > - > - /* Verify pointers */ > - if (!n_hdlc) > - return -EIO; > - > - if (n_hdlc->magic != HDLC_MAGIC) > - return -EIO; > > /* verify frame size */ > if (count > maxframe ) { > @@ -670,40 +629,14 @@ static ssize_t n_hdlc_tty_write(struct tty_struct *tty, struct file *file, > maxframe ); > count = maxframe; > } > - > - add_wait_queue(&tty->write_wait, &wait); > > - for (;;) { > - set_current_state(TASK_INTERRUPTIBLE); > - > - tbuf = n_hdlc_buf_get(&n_hdlc->tx_free_buf_list); > - if (tbuf) > - break; > - > - if (tty_io_nonblock(tty, file)) { > - error = -EAGAIN; > - break; > - } > - schedule(); > - > - n_hdlc = tty2n_hdlc (tty); > - if (!n_hdlc || n_hdlc->magic != HDLC_MAGIC || > - tty != n_hdlc->tty) { > - printk("n_hdlc_tty_write: %p invalid after wait!\n", n_hdlc); > - error = -EIO; > - break; > - } > - > - if (signal_pending(current)) { > - error = -EINTR; > - break; > - } > - } > - > - __set_current_state(TASK_RUNNING); > - remove_wait_queue(&tty->write_wait, &wait); > - > - if (!error) { > + if (wait_event_interruptible(tty->write_wait, > + (error = -EIO, n_hdlc = tty2n_hdlc(tty), /* Verify pointers */ > + !n_hdlc || n_hdlc->magic != HDLC_MAGIC || tty != n_hdlc->tty) || > + (tbuf = n_hdlc_buf_get(&n_hdlc->tx_free_buf_list)) != NULL || > + (error = -EAGAIN, tty_io_nonblock(tty, file)))) > + return -EINTR; This is even worse. So detto as above? > + if (tbuf) { > /* Retrieve the user's buffer */ > memcpy(tbuf->buf, data, count); > > @@ -711,8 +644,9 @@ static ssize_t n_hdlc_tty_write(struct tty_struct *tty, struct file *file, > tbuf->count = error = count; > n_hdlc_buf_put(&n_hdlc->tx_buf_list,tbuf); > n_hdlc_send_frames(n_hdlc,tty); > + } else if (error == -EIO) { > + printk("n_hdlc_tty_write: %p invalid!\n", n_hdlc); > } > - > return error; > > } /* end of n_hdlc_tty_write() */ > thanks, -- js suse labs ^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH] tty/n_hdlc: fix sleep in !TASK_RUNNING state warning 2019-01-03 9:09 ` Jiri Slaby @ 2019-01-03 11:32 ` Tetsuo Handa 2019-01-03 15:57 ` Paul Fulghum 0 siblings, 1 reply; 13+ messages in thread From: Tetsuo Handa @ 2019-01-03 11:32 UTC (permalink / raw) To: Jiri Slaby, Paul Fulghum; +Cc: Arnd Bergmann, gregkh, Alan Cox, linux-kernel On 2019/01/03 18:09, Jiri Slaby wrote: > On 02. 01. 19, 16:04, Tetsuo Handa wrote: >> + if (wait_event_interruptible(tty->read_wait, >> + (ret = -EIO, test_bit(TTY_OTHER_CLOSED, &tty->flags)) || >> + (ret = 0, tty_hung_up_p(file)) || >> + (rbuf = n_hdlc_buf_get(&n_hdlc->rx_buf_list)) != NULL || >> + (ret = -EAGAIN, tty_io_nonblock(tty, file)))) >> + return -EINTR; > > Oh, that looks really ugly. Could you move all this to a function > returning a bool and taking &ret and &rbuf as parameters? > OK. Something like this? From 725c55be437b6ce3b578a045cc7ddeeb2bbeb4b3 Mon Sep 17 00:00:00 2001 From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Date: Thu, 3 Jan 2019 20:29:49 +0900 Subject: [PATCH] tty/n_hdlc: Use wait_event_interruptible() and same sanity checks. We can use wait_event_interruptible() in order to make it easier to understand. Also, since the reason of using different level/frequency of sanity checks for read and write is unclear while nowadays we have rich fuzzing/sanitizing tools, let's use same sanity checks for read and write. Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> --- drivers/tty/n_hdlc.c | 154 ++++++++++++++++++++------------------------------- 1 file changed, 61 insertions(+), 93 deletions(-) diff --git a/drivers/tty/n_hdlc.c b/drivers/tty/n_hdlc.c index 8223d02..c497ef1 100644 --- a/drivers/tty/n_hdlc.c +++ b/drivers/tty/n_hdlc.c @@ -548,6 +548,27 @@ static void n_hdlc_tty_receive(struct tty_struct *tty, const __u8 *data, } /* end of n_hdlc_tty_receive() */ +static bool __n_hdlc_tty_read(struct tty_struct *tty, struct file *file, + struct n_hdlc *n_hdlc, int *ret, + struct n_hdlc_buf **rbuf) +{ + if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) { + *ret = -EIO; + return true; + } + if (tty_hung_up_p(file)) + return true; + *rbuf = n_hdlc_buf_get(&n_hdlc->rx_buf_list); + if (*rbuf) + return true; + /* no data */ + if (tty_io_nonblock(tty, file)) { + *ret = -EAGAIN; + return true; + } + return false; +} + /** * n_hdlc_tty_read - Called to retrieve one frame of data (if available) * @tty - pointer to tty instance data @@ -562,14 +583,13 @@ static ssize_t n_hdlc_tty_read(struct tty_struct *tty, struct file *file, { struct n_hdlc *n_hdlc = tty2n_hdlc(tty); int ret = 0; - struct n_hdlc_buf *rbuf; - DECLARE_WAITQUEUE(wait, current); + struct n_hdlc_buf *rbuf = NULL; if (debuglevel >= DEBUG_LEVEL_INFO) printk("%s(%d)n_hdlc_tty_read() called\n",__FILE__,__LINE__); /* Validate the pointers */ - if (!n_hdlc) + if (!n_hdlc || n_hdlc->magic != HDLC_MAGIC) return -EIO; /* verify user access to buffer */ @@ -579,60 +599,41 @@ static ssize_t n_hdlc_tty_read(struct tty_struct *tty, struct file *file, return -EFAULT; } - add_wait_queue(&tty->read_wait, &wait); - - for (;;) { - if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) { - ret = -EIO; - break; - } - if (tty_hung_up_p(file)) - break; - - set_current_state(TASK_INTERRUPTIBLE); - - rbuf = n_hdlc_buf_get(&n_hdlc->rx_buf_list); - if (rbuf) { - if (rbuf->count > nr) { - /* too large for caller's buffer */ - ret = -EOVERFLOW; - } else { - __set_current_state(TASK_RUNNING); - if (copy_to_user(buf, rbuf->buf, rbuf->count)) - ret = -EFAULT; - else - ret = rbuf->count; - } - - if (n_hdlc->rx_free_buf_list.count > - DEFAULT_RX_BUF_COUNT) - kfree(rbuf); - else - n_hdlc_buf_put(&n_hdlc->rx_free_buf_list, rbuf); - break; - } - - /* no data */ - if (tty_io_nonblock(tty, file)) { - ret = -EAGAIN; - break; - } - - schedule(); - - if (signal_pending(current)) { - ret = -EINTR; - break; - } + if (wait_event_interruptible(tty->read_wait, + __n_hdlc_tty_read(tty, file, n_hdlc, &ret, + &rbuf))) + return -EINTR; + if (rbuf) { + if (rbuf->count > nr) + /* too large for caller's buffer */ + ret = -EOVERFLOW; + else if (copy_to_user(buf, rbuf->buf, rbuf->count)) + ret = -EFAULT; + else + ret = rbuf->count; + if (n_hdlc->rx_free_buf_list.count > DEFAULT_RX_BUF_COUNT) + kfree(rbuf); + else + n_hdlc_buf_put(&n_hdlc->rx_free_buf_list, rbuf); } - - remove_wait_queue(&tty->read_wait, &wait); - __set_current_state(TASK_RUNNING); - return ret; } /* end of n_hdlc_tty_read() */ +static bool __n_hdlc_tty_write(struct tty_struct *tty, struct file *file, + struct n_hdlc *n_hdlc, int *error, + struct n_hdlc_buf **tbuf) +{ + *tbuf = n_hdlc_buf_get(&n_hdlc->tx_free_buf_list); + if (*tbuf) + return true; + if (tty_io_nonblock(tty, file)) { + *error = -EAGAIN; + return true; + } + return false; +} + /** * n_hdlc_tty_write - write a single frame of data to device * @tty - pointer to associated tty device instance data @@ -645,20 +646,16 @@ static ssize_t n_hdlc_tty_read(struct tty_struct *tty, struct file *file, static ssize_t n_hdlc_tty_write(struct tty_struct *tty, struct file *file, const unsigned char *data, size_t count) { - struct n_hdlc *n_hdlc = tty2n_hdlc (tty); + struct n_hdlc *n_hdlc = tty2n_hdlc(tty); int error = 0; - DECLARE_WAITQUEUE(wait, current); struct n_hdlc_buf *tbuf; if (debuglevel >= DEBUG_LEVEL_INFO) printk("%s(%d)n_hdlc_tty_write() called count=%zd\n", __FILE__,__LINE__,count); - - /* Verify pointers */ - if (!n_hdlc) - return -EIO; - if (n_hdlc->magic != HDLC_MAGIC) + /* Validate the pointers */ + if (!n_hdlc || n_hdlc->magic != HDLC_MAGIC) return -EIO; /* verify frame size */ @@ -670,40 +667,12 @@ static ssize_t n_hdlc_tty_write(struct tty_struct *tty, struct file *file, maxframe ); count = maxframe; } - - add_wait_queue(&tty->write_wait, &wait); - - for (;;) { - set_current_state(TASK_INTERRUPTIBLE); - - tbuf = n_hdlc_buf_get(&n_hdlc->tx_free_buf_list); - if (tbuf) - break; - - if (tty_io_nonblock(tty, file)) { - error = -EAGAIN; - break; - } - schedule(); - - n_hdlc = tty2n_hdlc (tty); - if (!n_hdlc || n_hdlc->magic != HDLC_MAGIC || - tty != n_hdlc->tty) { - printk("n_hdlc_tty_write: %p invalid after wait!\n", n_hdlc); - error = -EIO; - break; - } - - if (signal_pending(current)) { - error = -EINTR; - break; - } - } - - __set_current_state(TASK_RUNNING); - remove_wait_queue(&tty->write_wait, &wait); - if (!error) { + if (wait_event_interruptible(tty->write_wait, + __n_hdlc_tty_write(tty, file, n_hdlc, + &error, &tbuf))) + return -EINTR; + if (tbuf) { /* Retrieve the user's buffer */ memcpy(tbuf->buf, data, count); @@ -712,7 +681,6 @@ static ssize_t n_hdlc_tty_write(struct tty_struct *tty, struct file *file, n_hdlc_buf_put(&n_hdlc->tx_buf_list,tbuf); n_hdlc_send_frames(n_hdlc,tty); } - return error; } /* end of n_hdlc_tty_write() */ -- 1.8.3.1 ^ permalink raw reply related [flat|nested] 13+ messages in thread
* Re: [PATCH] tty/n_hdlc: fix sleep in !TASK_RUNNING state warning 2019-01-03 11:32 ` Tetsuo Handa @ 2019-01-03 15:57 ` Paul Fulghum 2019-01-04 10:23 ` Tetsuo Handa 0 siblings, 1 reply; 13+ messages in thread From: Paul Fulghum @ 2019-01-03 15:57 UTC (permalink / raw) To: Tetsuo Handa Cc: Jiri Slaby, Arnd Bergmann, Greg Kroah-Hartman, Alan Cox, linux-kernel > On Jan 3, 2019, at 3:32 AM, Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> wrote: > > On 2019/01/03 18:09, Jiri Slaby wrote: >> On 02. 01. 19, 16:04, Tetsuo Handa wrote: >>> + if (wait_event_interruptible(tty->read_wait, >>> + (ret = -EIO, test_bit(TTY_OTHER_CLOSED, &tty->flags)) || >>> + (ret = 0, tty_hung_up_p(file)) || >>> + (rbuf = n_hdlc_buf_get(&n_hdlc->rx_buf_list)) != NULL || >>> + (ret = -EAGAIN, tty_io_nonblock(tty, file)))) >>> + return -EINTR; >> >> Oh, that looks really ugly. Could you move all this to a function >> returning a bool and taking &ret and &rbuf as parameters? >> > > OK. Something like this? I agree with Jiri that placing all the conditional logic in a single expression is difficult to read. But exchanging that many locals with a separate function defeats the original purpose of simplifying code and this implementation changes the logic (write no longer checks for line discipline changing under it during wait). Converting to wait_event_interruptible where possible is a good goal but this instance may be better left alone. The current structure mirrors the existing n_tty line discipline. ^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH] tty/n_hdlc: fix sleep in !TASK_RUNNING state warning 2019-01-03 15:57 ` Paul Fulghum @ 2019-01-04 10:23 ` Tetsuo Handa 2019-01-04 13:57 ` Paul Fulghum 0 siblings, 1 reply; 13+ messages in thread From: Tetsuo Handa @ 2019-01-04 10:23 UTC (permalink / raw) To: Paul Fulghum Cc: Jiri Slaby, Arnd Bergmann, Greg Kroah-Hartman, Alan Cox, linux-kernel On 2019/01/04 0:57, Paul Fulghum wrote: >> On Jan 3, 2019, at 3:32 AM, Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> wrote: >> >> On 2019/01/03 18:09, Jiri Slaby wrote: >>> On 02. 01. 19, 16:04, Tetsuo Handa wrote: >>>> + if (wait_event_interruptible(tty->read_wait, >>>> + (ret = -EIO, test_bit(TTY_OTHER_CLOSED, &tty->flags)) || >>>> + (ret = 0, tty_hung_up_p(file)) || >>>> + (rbuf = n_hdlc_buf_get(&n_hdlc->rx_buf_list)) != NULL || >>>> + (ret = -EAGAIN, tty_io_nonblock(tty, file)))) >>>> + return -EINTR; >>> >>> Oh, that looks really ugly. Could you move all this to a function >>> returning a bool and taking &ret and &rbuf as parameters? >>> >> >> OK. Something like this? > > > I agree with Jiri that placing all the conditional logic in a single expression is difficult to read. > > But exchanging that many locals with a separate function defeats the original purpose of > simplifying code and this implementation changes the logic (write no > longer checks for line discipline changing under it during wait). Not only defeating the original purpose but also increasing object size. > > Converting to wait_event_interruptible where possible is a good goal but this instance > may be better left alone. The current structure mirrors the existing n_tty line discipline. But why not to clarify what are appropriate sanity checks? Currently, read side does not check "n_hdlc->magic != HDLC_MAGIC" case while write side does. If it is intended for catching memory corruption etc. then both sides should do the same thing. Currently, write side does not check "tty != n_hdlc->tty" case before schedule() while does after schedule(). If "tty != n_hdlc->tty" case can ever happen, what prevents n_hdlc_tty_write() from being called again after n_hdlc_tty_write() once returned with -EIO due to "tty != n_hdlc->tty" case? If it is intended for catching memory corruption etc. then both sides should check "tty != n_hdlc->tty" case. Current logic is unclear, in addition to want a cleanup for scripts/checkpatch.pl . total: 158 errors, 95 warnings, 994 lines checked ^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH] tty/n_hdlc: fix sleep in !TASK_RUNNING state warning 2019-01-04 10:23 ` Tetsuo Handa @ 2019-01-04 13:57 ` Paul Fulghum 0 siblings, 0 replies; 13+ messages in thread From: Paul Fulghum @ 2019-01-04 13:57 UTC (permalink / raw) To: Tetsuo Handa Cc: Jiri Slaby, Arnd Bergmann, Greg Kroah-Hartman, Alan Cox, linux-kernel > On Jan 4, 2019, at 2:23 AM, Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> wrote: > > But why not to clarify what are appropriate sanity checks? > ... > want a cleanup for scripts/checkpatch.pl . These are good goals. I avoid purely cosmetic patches. I do not object to cosmetic patches from others that do not change behavior. The checks that concern you deal with changing tty line disciplines. Dealing with line discipline changes has been an ongoing issue since n_hdlc was derived from other line disciplines 20 years ago, with major overhauls along the way. It is complex: driver layers shifting during operation while dealing properly with opens, closes, hangups, and sleeping operations. Patches have been added to the latest unreleased kernel to address line discipline changes, it is still evolving. Why are the existing line discipline checks in n_hdlc where they are? Becasue that’s how they evolved from where they started to accomodate these changes. There are not many and their function is known: has the line discipline changed at that point? I know that is not satisfying but coming up with a definitive comment saying a check is absolutely required in one place and not in another requires more insight into the long history of a moving target than I have. Without that insight I would not alter existing checks in code that is not causing problems. ^ permalink raw reply [flat|nested] 13+ messages in thread
end of thread, other threads:[~2019-01-10 12:26 UTC | newest]
Thread overview: 13+ messages (download: mbox.gz / follow: Atom feed)
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2018-12-29 0:41 WARNING in __might_sleep (2) syzbot
2018-12-29 11:48 ` [PATCH] tty/n_hdlc: fix sleep in !TASK_RUNNING state warning Tetsuo Handa
2019-01-01 3:13 ` Paul Fulghum
2019-01-01 20:28 ` [PATCH] tty/n_hdlc: fix __might_sleep warning Paul Fulghum
2019-01-10 11:38 ` Tetsuo Handa
2019-01-10 12:25 ` Arnd Bergmann
[not found] ` <FEBFE826-8D27-4A0B-86A5-BA559921CADC@microgate.com>
2019-01-02 15:04 ` [PATCH] tty/n_hdlc: fix sleep in !TASK_RUNNING state warning Tetsuo Handa
2019-01-02 20:55 ` Paul Fulghum
2019-01-03 9:09 ` Jiri Slaby
2019-01-03 11:32 ` Tetsuo Handa
2019-01-03 15:57 ` Paul Fulghum
2019-01-04 10:23 ` Tetsuo Handa
2019-01-04 13:57 ` Paul Fulghum
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