linux/drivers/tty/vt/selection.c

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License cleanup: add SPDX GPL-2.0 license identifier to files with no license Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-01 14:07:57 +00:00
// SPDX-License-Identifier: GPL-2.0
/*
* This module exports the functions:
*
* 'int set_selection_user(struct tiocl_selection __user *,
* struct tty_struct *)'
* 'int set_selection_kernel(struct tiocl_selection *, struct tty_struct *)'
* 'void clear_selection(void)'
* 'int paste_selection(struct tty_struct *)'
* 'int sel_loadlut(char __user *)'
*
* Now that /dev/vcs exists, most of this can disappear again.
*/
#include <linux/module.h>
#include <linux/tty.h>
#include <linux/sched.h>
#include <linux/mm.h>
vt: selection, close sel_buffer race syzkaller reported this UAF: BUG: KASAN: use-after-free in n_tty_receive_buf_common+0x2481/0x2940 drivers/tty/n_tty.c:1741 Read of size 1 at addr ffff8880089e40e9 by task syz-executor.1/13184 CPU: 0 PID: 13184 Comm: syz-executor.1 Not tainted 5.4.7 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 Call Trace: ... kasan_report+0xe/0x20 mm/kasan/common.c:634 n_tty_receive_buf_common+0x2481/0x2940 drivers/tty/n_tty.c:1741 tty_ldisc_receive_buf+0xac/0x190 drivers/tty/tty_buffer.c:461 paste_selection+0x297/0x400 drivers/tty/vt/selection.c:372 tioclinux+0x20d/0x4e0 drivers/tty/vt/vt.c:3044 vt_ioctl+0x1bcf/0x28d0 drivers/tty/vt/vt_ioctl.c:364 tty_ioctl+0x525/0x15a0 drivers/tty/tty_io.c:2657 vfs_ioctl fs/ioctl.c:47 [inline] It is due to a race between parallel paste_selection (TIOCL_PASTESEL) and set_selection_user (TIOCL_SETSEL) invocations. One uses sel_buffer, while the other frees it and reallocates a new one for another selection. Add a mutex to close this race. The mutex takes care properly of sel_buffer and sel_buffer_lth only. The other selection global variables (like sel_start, sel_end, and sel_cons) are protected only in set_selection_user. The other functions need quite some more work to close the races of the variables there. This is going to happen later. This likely fixes (I am unsure as there is no reproducer provided) bug 206361 too. It was marked as CVE-2020-8648. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Reported-by: syzbot+59997e8d5cbdc486e6f6@syzkaller.appspotmail.com References: https://bugzilla.kernel.org/show_bug.cgi?id=206361 Cc: stable <stable@vger.kernel.org> Link: https://lore.kernel.org/r/20200210081131.23572-2-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-10 08:11:31 +00:00
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/uaccess.h>
#include <linux/kbd_kern.h>
#include <linux/vt_kern.h>
#include <linux/consolemap.h>
#include <linux/selection.h>
#include <linux/tiocl.h>
#include <linux/console.h>
#include <linux/tty_flip.h>
#include <linux/sched/signal.h>
/* Don't take this from <ctype.h>: 011-015 on the screen aren't spaces */
#define is_space_on_vt(c) ((c) == ' ')
/* FIXME: all this needs locking */
static struct vc_selection {
struct mutex lock;
struct vc_data *cons; /* must not be deallocated */
char *buffer;
unsigned int buf_len;
volatile int start; /* cleared by clear_selection */
int end;
} vc_sel = {
.lock = __MUTEX_INITIALIZER(vc_sel.lock),
.start = -1,
};
/* clear_selection, highlight and highlight_pointer can be called
from interrupt (via scrollback/front) */
/* set reverse video on characters s-e of console with selection. */
static inline void highlight(const int s, const int e)
{
invert_screen(vc_sel.cons, s, e-s+2, true);
}
/* use complementary color to show the pointer */
static inline void highlight_pointer(const int where)
{
complement_pos(vc_sel.cons, where);
}
static u32
sel_pos(int n, bool unicode)
{
if (unicode)
return screen_glyph_unicode(vc_sel.cons, n / 2);
return inverse_translate(vc_sel.cons, screen_glyph(vc_sel.cons, n), 0);
}
/**
* clear_selection - remove current selection
*
* Remove the current selection highlight, if any from the console
* holding the selection. The caller must hold the console lock.
*/
void clear_selection(void)
{
highlight_pointer(-1); /* hide the pointer */
if (vc_sel.start != -1) {
highlight(vc_sel.start, vc_sel.end);
vc_sel.start = -1;
}
}
EXPORT_SYMBOL_GPL(clear_selection);
bool vc_is_sel(struct vc_data *vc)
{
return vc == vc_sel.cons;
}
/*
* User settable table: what characters are to be considered alphabetic?
* 128 bits. Locked by the console lock.
*/
static u32 inwordLut[]={
0x00000000, /* control chars */
0x03FFE000, /* digits and "-./" */
0x87FFFFFE, /* uppercase and '_' */
0x07FFFFFE, /* lowercase */
};
static inline int inword(const u32 c)
{
return c > 0x7f || (( inwordLut[c>>5] >> (c & 0x1F) ) & 1);
}
/**
* sel_loadlut() - load the LUT table
* @p: user table
*
* Load the LUT table from user space. The caller must hold the console
* lock. Make a temporary copy so a partial update doesn't make a mess.
*/
int sel_loadlut(char __user *p)
{
u32 tmplut[ARRAY_SIZE(inwordLut)];
if (copy_from_user(tmplut, (u32 __user *)(p+4), sizeof(inwordLut)))
return -EFAULT;
memcpy(inwordLut, tmplut, sizeof(inwordLut));
return 0;
}
/* does screen address p correspond to character at LH/RH edge of screen? */
static inline int atedge(const int p, int size_row)
{
return (!(p % size_row) || !((p + 2) % size_row));
}
/* stores the char in UTF8 and returns the number of bytes used (1-4) */
static int store_utf8(u32 c, char *p)
{
if (c < 0x80) {
/* 0******* */
p[0] = c;
return 1;
} else if (c < 0x800) {
/* 110***** 10****** */
p[0] = 0xc0 | (c >> 6);
p[1] = 0x80 | (c & 0x3f);
return 2;
} else if (c < 0x10000) {
/* 1110**** 10****** 10****** */
p[0] = 0xe0 | (c >> 12);
p[1] = 0x80 | ((c >> 6) & 0x3f);
p[2] = 0x80 | (c & 0x3f);
return 3;
} else if (c < 0x110000) {
/* 11110*** 10****** 10****** 10****** */
p[0] = 0xf0 | (c >> 18);
p[1] = 0x80 | ((c >> 12) & 0x3f);
p[2] = 0x80 | ((c >> 6) & 0x3f);
p[3] = 0x80 | (c & 0x3f);
return 4;
} else {
/* outside Unicode, replace with U+FFFD */
p[0] = 0xef;
p[1] = 0xbf;
p[2] = 0xbd;
return 3;
}
}
/**
* set_selection_user - set the current selection.
* @sel: user selection info
* @tty: the console tty
*
* Invoked by the ioctl handle for the vt layer.
*
* The entire selection process is managed under the console_lock. It's
* a lot under the lock but its hardly a performance path
*/
int set_selection_user(const struct tiocl_selection __user *sel,
struct tty_struct *tty)
{
struct tiocl_selection v;
if (copy_from_user(&v, sel, sizeof(*sel)))
return -EFAULT;
return set_selection_kernel(&v, tty);
}
static int vc_selection_store_chars(struct vc_data *vc, bool unicode)
{
char *bp, *obp;
unsigned int i;
/* Allocate a new buffer before freeing the old one ... */
/* chars can take up to 4 bytes with unicode */
bp = kmalloc_array((vc_sel.end - vc_sel.start) / 2 + 1, unicode ? 4 : 1,
GFP_KERNEL | __GFP_NOWARN);
if (!bp) {
printk(KERN_WARNING "selection: kmalloc() failed\n");
clear_selection();
return -ENOMEM;
}
kfree(vc_sel.buffer);
vc_sel.buffer = bp;
obp = bp;
for (i = vc_sel.start; i <= vc_sel.end; i += 2) {
u32 c = sel_pos(i, unicode);
if (unicode)
bp += store_utf8(c, bp);
else
*bp++ = c;
if (!is_space_on_vt(c))
obp = bp;
if (!((i + 2) % vc->vc_size_row)) {
/* strip trailing blanks from line and add newline,
unless non-space at end of line. */
if (obp != bp) {
bp = obp;
*bp++ = '\r';
}
obp = bp;
}
}
vc_sel.buf_len = bp - vc_sel.buffer;
return 0;
}
static int vc_do_selection(struct vc_data *vc, unsigned short mode, int ps,
int pe)
{
int new_sel_start, new_sel_end, spc;
bool unicode = vt_do_kdgkbmode(fg_console) == K_UNICODE;
switch (mode) {
case TIOCL_SELCHAR: /* character-by-character selection */
new_sel_start = ps;
new_sel_end = pe;
break;
case TIOCL_SELWORD: /* word-by-word selection */
spc = is_space_on_vt(sel_pos(ps, unicode));
for (new_sel_start = ps; ; ps -= 2) {
if ((spc && !is_space_on_vt(sel_pos(ps, unicode))) ||
(!spc && !inword(sel_pos(ps, unicode))))
break;
new_sel_start = ps;
if (!(ps % vc->vc_size_row))
break;
}
spc = is_space_on_vt(sel_pos(pe, unicode));
for (new_sel_end = pe; ; pe += 2) {
if ((spc && !is_space_on_vt(sel_pos(pe, unicode))) ||
(!spc && !inword(sel_pos(pe, unicode))))
break;
new_sel_end = pe;
if (!((pe + 2) % vc->vc_size_row))
break;
}
break;
case TIOCL_SELLINE: /* line-by-line selection */
new_sel_start = rounddown(ps, vc->vc_size_row);
new_sel_end = rounddown(pe, vc->vc_size_row) +
vc->vc_size_row - 2;
break;
case TIOCL_SELPOINTER:
highlight_pointer(pe);
return 0;
default:
return -EINVAL;
}
/* remove the pointer */
highlight_pointer(-1);
/* select to end of line if on trailing space */
if (new_sel_end > new_sel_start &&
!atedge(new_sel_end, vc->vc_size_row) &&
is_space_on_vt(sel_pos(new_sel_end, unicode))) {
for (pe = new_sel_end + 2; ; pe += 2)
if (!is_space_on_vt(sel_pos(pe, unicode)) ||
atedge(pe, vc->vc_size_row))
break;
if (is_space_on_vt(sel_pos(pe, unicode)))
new_sel_end = pe;
}
if (vc_sel.start == -1) /* no current selection */
highlight(new_sel_start, new_sel_end);
else if (new_sel_start == vc_sel.start)
{
if (new_sel_end == vc_sel.end) /* no action required */
vt: selection, push sel_lock up sel_lock cannot nest in the console lock. Thanks to syzkaller, the kernel states firmly: > WARNING: possible circular locking dependency detected > 5.6.0-rc3-syzkaller #0 Not tainted > ------------------------------------------------------ > syz-executor.4/20336 is trying to acquire lock: > ffff8880a2e952a0 (&tty->termios_rwsem){++++}, at: tty_unthrottle+0x22/0x100 drivers/tty/tty_ioctl.c:136 > > but task is already holding lock: > ffffffff89462e70 (sel_lock){+.+.}, at: paste_selection+0x118/0x470 drivers/tty/vt/selection.c:374 > > which lock already depends on the new lock. > > the existing dependency chain (in reverse order) is: > > -> #2 (sel_lock){+.+.}: > mutex_lock_nested+0x1b/0x30 kernel/locking/mutex.c:1118 > set_selection_kernel+0x3b8/0x18a0 drivers/tty/vt/selection.c:217 > set_selection_user+0x63/0x80 drivers/tty/vt/selection.c:181 > tioclinux+0x103/0x530 drivers/tty/vt/vt.c:3050 > vt_ioctl+0x3f1/0x3a30 drivers/tty/vt/vt_ioctl.c:364 This is ioctl(TIOCL_SETSEL). Locks held on the path: console_lock -> sel_lock > -> #1 (console_lock){+.+.}: > console_lock+0x46/0x70 kernel/printk/printk.c:2289 > con_flush_chars+0x50/0x650 drivers/tty/vt/vt.c:3223 > n_tty_write+0xeae/0x1200 drivers/tty/n_tty.c:2350 > do_tty_write drivers/tty/tty_io.c:962 [inline] > tty_write+0x5a1/0x950 drivers/tty/tty_io.c:1046 This is write(). Locks held on the path: termios_rwsem -> console_lock > -> #0 (&tty->termios_rwsem){++++}: > down_write+0x57/0x140 kernel/locking/rwsem.c:1534 > tty_unthrottle+0x22/0x100 drivers/tty/tty_ioctl.c:136 > mkiss_receive_buf+0x12aa/0x1340 drivers/net/hamradio/mkiss.c:902 > tty_ldisc_receive_buf+0x12f/0x170 drivers/tty/tty_buffer.c:465 > paste_selection+0x346/0x470 drivers/tty/vt/selection.c:389 > tioclinux+0x121/0x530 drivers/tty/vt/vt.c:3055 > vt_ioctl+0x3f1/0x3a30 drivers/tty/vt/vt_ioctl.c:364 This is ioctl(TIOCL_PASTESEL). Locks held on the path: sel_lock -> termios_rwsem > other info that might help us debug this: > > Chain exists of: > &tty->termios_rwsem --> console_lock --> sel_lock Clearly. From the above, we have: console_lock -> sel_lock sel_lock -> termios_rwsem termios_rwsem -> console_lock Fix this by reversing the console_lock -> sel_lock dependency in ioctl(TIOCL_SETSEL). First, lock sel_lock, then console_lock. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Reported-by: syzbot+26183d9746e62da329b8@syzkaller.appspotmail.com Fixes: 07e6124a1a46 ("vt: selection, close sel_buffer race") Cc: stable <stable@vger.kernel.org> Link: https://lore.kernel.org/r/20200228115406.5735-2-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-28 11:54:06 +00:00
return 0;
else if (new_sel_end > vc_sel.end) /* extend to right */
highlight(vc_sel.end + 2, new_sel_end);
else /* contract from right */
highlight(new_sel_end + 2, vc_sel.end);
}
else if (new_sel_end == vc_sel.end)
{
if (new_sel_start < vc_sel.start) /* extend to left */
highlight(new_sel_start, vc_sel.start - 2);
else /* contract from left */
highlight(vc_sel.start, new_sel_start - 2);
}
else /* some other case; start selection from scratch */
{
clear_selection();
highlight(new_sel_start, new_sel_end);
}
vc_sel.start = new_sel_start;
vc_sel.end = new_sel_end;
return vc_selection_store_chars(vc, unicode);
}
static int vc_selection(struct vc_data *vc, struct tiocl_selection *v,
struct tty_struct *tty)
{
int ps, pe;
poke_blanked_console();
if (v->sel_mode == TIOCL_SELCLEAR) {
/* useful for screendump without selection highlights */
clear_selection();
return 0;
}
v->xs = min_t(u16, v->xs - 1, vc->vc_cols - 1);
v->ys = min_t(u16, v->ys - 1, vc->vc_rows - 1);
v->xe = min_t(u16, v->xe - 1, vc->vc_cols - 1);
v->ye = min_t(u16, v->ye - 1, vc->vc_rows - 1);
if (mouse_reporting() && (v->sel_mode & TIOCL_SELMOUSEREPORT)) {
mouse_report(tty, v->sel_mode & TIOCL_SELBUTTONMASK, v->xs,
v->ys);
return 0;
}
ps = v->ys * vc->vc_size_row + (v->xs << 1);
pe = v->ye * vc->vc_size_row + (v->xe << 1);
if (ps > pe) /* make vc_sel.start <= vc_sel.end */
swap(ps, pe);
if (vc_sel.cons != vc) {
clear_selection();
vc_sel.cons = vc;
}
return vc_do_selection(vc, v->sel_mode, ps, pe);
}
int set_selection_kernel(struct tiocl_selection *v, struct tty_struct *tty)
{
int ret;
mutex_lock(&vc_sel.lock);
console_lock();
ret = vc_selection(vc_cons[fg_console].d, v, tty);
console_unlock();
mutex_unlock(&vc_sel.lock);
vt: selection, close sel_buffer race syzkaller reported this UAF: BUG: KASAN: use-after-free in n_tty_receive_buf_common+0x2481/0x2940 drivers/tty/n_tty.c:1741 Read of size 1 at addr ffff8880089e40e9 by task syz-executor.1/13184 CPU: 0 PID: 13184 Comm: syz-executor.1 Not tainted 5.4.7 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 Call Trace: ... kasan_report+0xe/0x20 mm/kasan/common.c:634 n_tty_receive_buf_common+0x2481/0x2940 drivers/tty/n_tty.c:1741 tty_ldisc_receive_buf+0xac/0x190 drivers/tty/tty_buffer.c:461 paste_selection+0x297/0x400 drivers/tty/vt/selection.c:372 tioclinux+0x20d/0x4e0 drivers/tty/vt/vt.c:3044 vt_ioctl+0x1bcf/0x28d0 drivers/tty/vt/vt_ioctl.c:364 tty_ioctl+0x525/0x15a0 drivers/tty/tty_io.c:2657 vfs_ioctl fs/ioctl.c:47 [inline] It is due to a race between parallel paste_selection (TIOCL_PASTESEL) and set_selection_user (TIOCL_SETSEL) invocations. One uses sel_buffer, while the other frees it and reallocates a new one for another selection. Add a mutex to close this race. The mutex takes care properly of sel_buffer and sel_buffer_lth only. The other selection global variables (like sel_start, sel_end, and sel_cons) are protected only in set_selection_user. The other functions need quite some more work to close the races of the variables there. This is going to happen later. This likely fixes (I am unsure as there is no reproducer provided) bug 206361 too. It was marked as CVE-2020-8648. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Reported-by: syzbot+59997e8d5cbdc486e6f6@syzkaller.appspotmail.com References: https://bugzilla.kernel.org/show_bug.cgi?id=206361 Cc: stable <stable@vger.kernel.org> Link: https://lore.kernel.org/r/20200210081131.23572-2-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-10 08:11:31 +00:00
return ret;
}
EXPORT_SYMBOL_GPL(set_selection_kernel);
/* Insert the contents of the selection buffer into the
* queue of the tty associated with the current console.
* Invoked by ioctl().
*
* Locking: called without locks. Calls the ldisc wrongly with
* unsafe methods,
*/
int paste_selection(struct tty_struct *tty)
{
struct vc_data *vc = tty->driver_data;
[PATCH] TTY layer buffering revamp The API and code have been through various bits of initial review by serial driver people but they definitely need to live somewhere for a while so the unconverted drivers can get knocked into shape, existing drivers that have been updated can be better tuned and bugs whacked out. This replaces the tty flip buffers with kmalloc objects in rings. In the normal situation for an IRQ driven serial port at typical speeds the behaviour is pretty much the same, two buffers end up allocated and the kernel cycles between them as before. When there are delays or at high speed we now behave far better as the buffer pool can grow a bit rather than lose characters. This also means that we can operate at higher speeds reliably. For drivers that receive characters in blocks (DMA based, USB and especially virtualisation) the layer allows a lot of driver specific code that works around the tty layer with private secondary queues to be removed. The IBM folks need this sort of layer, the smart serial port people do, the virtualisers do (because a virtualised tty typically operates at infinite speed rather than emulating 9600 baud). Finally many drivers had invalid and unsafe attempts to avoid buffer overflows by directly invoking tty methods extracted out of the innards of work queue structs. These are no longer needed and all go away. That fixes various random hangs with serial ports on overflow. The other change in here is to optimise the receive_room path that is used by some callers. It turns out that only one ldisc uses receive room except asa constant and it updates it far far less than the value is read. We thus make it a variable not a function call. I expect the code to contain bugs due to the size alone but I'll be watching and squashing them and feeding out new patches as it goes. Because the buffers now dynamically expand you should only run out of buffering when the kernel runs out of memory for real. That means a lot of the horrible hacks high performance drivers used to do just aren't needed any more. Description: tty_insert_flip_char is an old API and continues to work as before, as does tty_flip_buffer_push() [this is why many drivers dont need modification]. It does now also return the number of chars inserted There are also tty_buffer_request_room(tty, len) which asks for a buffer block of the length requested and returns the space found. This improves efficiency with hardware that knows how much to transfer. and tty_insert_flip_string_flags(tty, str, flags, len) to insert a string of characters and flags For a smart interface the usual code is len = tty_request_buffer_room(tty, amount_hardware_says); tty_insert_flip_string(tty, buffer_from_card, len); More description! At the moment tty buffers are attached directly to the tty. This is causing a lot of the problems related to tty layer locking, also problems at high speed and also with bursty data (such as occurs in virtualised environments) I'm working on ripping out the flip buffers and replacing them with a pool of dynamically allocated buffers. This allows both for old style "byte I/O" devices and also helps virtualisation and smart devices where large blocks of data suddenely materialise and need storing. So far so good. Lots of drivers reference tty->flip.*. Several of them also call directly and unsafely into function pointers it provides. This will all break. Most drivers can use tty_insert_flip_char which can be kept as an API but others need more. At the moment I've added the following interfaces, if people think more will be needed now is a good time to say int tty_buffer_request_room(tty, size) Try and ensure at least size bytes are available, returns actual room (may be zero). At the moment it just uses the flipbuf space but that will change. Repeated calls without characters being added are not cumulative. (ie if you call it with 1, 1, 1, and then 4 you'll have four characters of space. The other functions will also try and grow buffers in future but this will be a more efficient way when you know block sizes. int tty_insert_flip_char(tty, ch, flag) As before insert a character if there is room. Now returns 1 for success, 0 for failure. int tty_insert_flip_string(tty, str, len) Insert a block of non error characters. Returns the number inserted. int tty_prepare_flip_string(tty, strptr, len) Adjust the buffer to allow len characters to be added. Returns a buffer pointer in strptr and the length available. This allows for hardware that needs to use functions like insl or mencpy_fromio. Signed-off-by: Alan Cox <alan@redhat.com> Cc: Paul Fulghum <paulkf@microgate.com> Signed-off-by: Hirokazu Takata <takata@linux-m32r.org> Signed-off-by: Serge Hallyn <serue@us.ibm.com> Signed-off-by: Jeff Dike <jdike@addtoit.com> Signed-off-by: John Hawkes <hawkes@sgi.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-10 04:54:13 +00:00
int pasted = 0;
unsigned int count;
struct tty_ldisc *ld;
DECLARE_WAITQUEUE(wait, current);
int ret = 0;
console_lock();
poke_blanked_console();
console_unlock();
ld = tty_ldisc_ref_wait(tty);
if (!ld)
return -EIO; /* ldisc was hung up */
tty_buffer_lock_exclusive(&vc->port);
add_wait_queue(&vc->paste_wait, &wait);
mutex_lock(&vc_sel.lock);
while (vc_sel.buffer && vc_sel.buf_len > pasted) {
set_current_state(TASK_INTERRUPTIBLE);
if (signal_pending(current)) {
ret = -EINTR;
break;
}
if (tty_throttled(tty)) {
mutex_unlock(&vc_sel.lock);
schedule();
mutex_lock(&vc_sel.lock);
continue;
}
tty: vt: Fix !TASK_RUNNING diagnostic warning from paste_selection() Pasting text with gpm on a VC produced warning [1]. Reset task state to TASK_RUNNING in the paste_selection() loop, if the loop did not sleep. [1] WARNING: CPU: 6 PID: 1960 at /home/peter/src/kernels/mainline/kernel/sched/core.c:7286 __might_sleep+0x7f/0x90() do not call blocking ops when !TASK_RUNNING; state=1 set at [<ffffffff8151805e>] paste_selection+0x9e/0x1a0 Modules linked in: btrfs xor raid6_pq ufs qnx4 hfsplus hfs minix ntfs msdos jfs xfs libcrc32c ..... CPU: 6 PID: 1960 Comm: gpm Not tainted 4.1.0-rc7+tty-xeon+debug #rc7+tty Hardware name: Dell Inc. Precision WorkStation T5400 /0RW203, BIOS A11 04/30/2012 ffffffff81c9c0a0 ffff8802b0fd3ac8 ffffffff8185778a 0000000000000001 ffff8802b0fd3b18 ffff8802b0fd3b08 ffffffff8108039a ffffffff82ae8510 ffffffff81c9ce00 0000000000000015 0000000000000000 0000000000000000 Call Trace: [<ffffffff8185778a>] dump_stack+0x4f/0x7b [<ffffffff8108039a>] warn_slowpath_common+0x8a/0xc0 [<ffffffff81080416>] warn_slowpath_fmt+0x46/0x50 [<ffffffff810ddced>] ? __lock_acquire+0xe2d/0x13a0 [<ffffffff8151805e>] ? paste_selection+0x9e/0x1a0 [<ffffffff8151805e>] ? paste_selection+0x9e/0x1a0 [<ffffffff810ad4ff>] __might_sleep+0x7f/0x90 [<ffffffff8185f76a>] down_read+0x2a/0xa0 [<ffffffff810bb1d8>] ? sched_clock_cpu+0xb8/0xe0 [<ffffffff8150d1dc>] n_tty_receive_buf_common+0x4c/0xba0 [<ffffffff810dc875>] ? mark_held_locks+0x75/0xa0 [<ffffffff81861c95>] ? _raw_spin_unlock_irqrestore+0x65/0x80 [<ffffffff810b49a1>] ? get_parent_ip+0x11/0x50 [<ffffffff8150dd44>] n_tty_receive_buf2+0x14/0x20 [<ffffffff81518117>] paste_selection+0x157/0x1a0 [<ffffffff810b77b0>] ? wake_up_state+0x20/0x20 [<ffffffff815203f8>] tioclinux+0xb8/0x2c0 [<ffffffff81515bfe>] vt_ioctl+0xaee/0x11a0 [<ffffffff810baf75>] ? sched_clock_local+0x25/0x90 [<ffffffff810bbe11>] ? vtime_account_user+0x91/0xa0 [<ffffffff8150810c>] tty_ioctl+0x20c/0xe20 [<ffffffff810bbe11>] ? vtime_account_user+0x91/0xa0 [<ffffffff810b49a1>] ? get_parent_ip+0x11/0x50 [<ffffffff810b4a69>] ? preempt_count_sub+0x49/0x50 [<ffffffff811ab71c>] ? context_tracking_exit+0x5c/0x290 [<ffffffff811ab71c>] ? context_tracking_exit+0x5c/0x290 [<ffffffff81248b98>] do_vfs_ioctl+0x318/0x570 [<ffffffff810dca8d>] ? trace_hardirqs_on+0xd/0x10 [<ffffffff810dc9b5>] ? trace_hardirqs_on_caller+0x115/0x1e0 [<ffffffff81254acc>] ? __fget_light+0x6c/0xa0 [<ffffffff81248e71>] SyS_ioctl+0x81/0xa0 [<ffffffff81862832>] system_call_fastpath+0x16/0x7a Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-07-13 00:47:35 +00:00
__set_current_state(TASK_RUNNING);
count = vc_sel.buf_len - pasted;
count = tty_ldisc_receive_buf(ld, vc_sel.buffer + pasted, NULL,
count);
pasted += count;
}
mutex_unlock(&vc_sel.lock);
remove_wait_queue(&vc->paste_wait, &wait);
__set_current_state(TASK_RUNNING);
tty_buffer_unlock_exclusive(&vc->port);
tty_ldisc_deref(ld);
return ret;
}
EXPORT_SYMBOL_GPL(paste_selection);