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| author | Ingo Molnar <mingo@elte.hu> | 2008-05-14 17:11:46 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-05-15 10:19:30 -0700 |
| commit | 487ad7efbf6b0ec338cdfc2a7b0fbeb53f17a94c (patch) | |
| tree | e2bc37cc97680403bf664a5944b10cdd907b9f10 /drivers/char | |
| parent | 8568dae21e186fbb111bbe6583033a33fe26f83d (diff) | |
| download | linux-487ad7efbf6b0ec338cdfc2a7b0fbeb53f17a94c.tar.gz linux-487ad7efbf6b0ec338cdfc2a7b0fbeb53f17a94c.tar.bz2 linux-487ad7efbf6b0ec338cdfc2a7b0fbeb53f17a94c.zip | |
tty: fix BKL related leak and crash
Enabling the BKL to be lockdep tracked uncovered the following
upstream kernel bug in the tty code, which caused a BKL
reference leak:
================================================
[ BUG: lock held when returning to user space! ]
------------------------------------------------
dmesg/3121 is leaving the kernel with locks still held!
1 lock held by dmesg/3121:
#0: (kernel_mutex){--..}, at: [<c02f34d9>] opost+0x24/0x194
this might explain some of the atomicity warnings and crashes
that -tip tree testing has been experiencing since the BKL
was converted back to a spinlock.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/char')
| -rw-r--r-- | drivers/char/n_tty.c | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/drivers/char/n_tty.c b/drivers/char/n_tty.c index 19105ec203f7..8096389b0dc2 100644 --- a/drivers/char/n_tty.c +++ b/drivers/char/n_tty.c @@ -282,16 +282,20 @@ static int opost(unsigned char c, struct tty_struct *tty) if (O_ONLRET(tty)) tty->column = 0; if (O_ONLCR(tty)) { - if (space < 2) + if (space < 2) { + unlock_kernel(); return -1; + } tty_put_char(tty, '\r'); tty->column = 0; } tty->canon_column = tty->column; break; case '\r': - if (O_ONOCR(tty) && tty->column == 0) + if (O_ONOCR(tty) && tty->column == 0) { + unlock_kernel(); return 0; + } if (O_OCRNL(tty)) { c = '\n'; if (O_ONLRET(tty)) @@ -303,10 +307,13 @@ static int opost(unsigned char c, struct tty_struct *tty) case '\t': spaces = 8 - (tty->column & 7); if (O_TABDLY(tty) == XTABS) { - if (space < spaces) + if (space < spaces) { + unlock_kernel(); return -1; + } tty->column += spaces; tty->ops->write(tty, " ", spaces); + unlock_kernel(); return 0; } tty->column += spaces; |