linux-stable.git/drivers/block/floppy.c, branch v4.7.3

Revert "floppy: fix open(O_ACCMODE) for ioctl-only open"

2016-09-07T06:34:53+00:00

commit 468c298ad3ed3f0d94a65f8ca00f6bfc6c2b4e33 upstream.

This reverts commit ff06db1efb2ad6db06eb5b99b88a0c15a9cc9b0e.

Signed-off-by: Greg Kroah-Hartman

floppy: fix open(O_ACCMODE) for ioctl-only open

2016-08-20T16:11:01+00:00

commit ff06db1efb2ad6db06eb5b99b88a0c15a9cc9b0e upstream.

Commit 09954bad4 ("floppy: refactor open() flags handling"), as a
side-effect, causes open(/dev/fdX, O_ACCMODE) to fail. It turns out that
this is being used setfdprm userspace for ioctl-only open().

Reintroduce back the original behavior wrt !(FMODE_READ|FMODE_WRITE)
modes, while still keeping the original O_NDELAY bug fixed.

Reported-by: Wim Osterholt 
Tested-by: Wim Osterholt 
Signed-off-by: Jiri Kosina 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

floppy: refactor open() flags handling

2016-02-06T22:00:22+00:00

In case /dev/fdX is open with O_NDELAY / O_NONBLOCK, floppy_open() immediately
succeeds, without performing any further media / controller preparations.
That's "correct" wrt. the NODELAY flag, but is hardly correct wrt. the rest
of the floppy driver, that is not really O_NONBLOCK ready, at all. Therefore
it's not too surprising, that subsequent attempts to work with the
filedescriptor produce bad results. Namely, syzkaller tool has been able
to livelock mmap() on the returned fd to keep waiting on the page unlock
bit forever.

Quite frankly, I have trouble defining what non-blocking behavior would be for
floppies. Is waiting ages for the driver to actually succeed reading a sector
blocking operation? Is waiting for drive motor to start blocking operation? How
about in case of virtualized floppies?

One option would be returning EWOULDBLOCK in case O_NDLEAY / O_NONBLOCK is
being passed to open(). That has a theoretical potential of breaking some
arcane and archaic userspace though.

Let's take a more conservative aproach, and accept the O_NDLEAY flag, and let
the driver behave as usual.

While at it, clean up a bit handling of !(mode & (FMODE_READ|FMODE_WRITE))
case and return EINVAL instead of succeeding as well.

Spotted by syzkaller tool.

Reported-by: Dmitry Vyukov 
Tested-by: Dmitry Vyukov 
Signed-off-by: Jiri Kosina

Merge branch 'for-4.5/for-jens' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/linux-block into for-linus

2016-02-01T16:08:39+00:00

Locking fix from Jiri

floppy: fix lock_fdc() signal handling

2016-02-01T10:19:17+00:00

floppy_revalidate() doesn't perform any error handling on lock_fdc()
result. lock_fdc() might actually be interrupted by a signal (it waits for
fdc becoming non-busy interruptibly). In such case, floppy_revalidate()
proceeds as if it had claimed the lock, but it fact it doesn't.

In case of multiple threads trying to open("/dev/fdX"), this leads to
serious corruptions all over the place, because all of a sudden there is
no critical section protection (that'd otherwise be guaranteed by locked
fd) whatsoever.

While at this, fix the fact that the 'interruptible' parameter to
lock_fdc() doesn't make any sense whatsoever, because we always wait
interruptibly anyway.

Most of the lock_fdc() callsites do properly handle error (and propagate
EINTR), but floppy_revalidate() and floppy_check_events() don't. Fix this.

Spotted by 'syzkaller' tool.

Reported-by: Dmitry Vyukov 
Tested-by: Dmitry Vyukov 
Signed-off-by: Jiri Kosina

floppy: make local variable non-static

2015-12-08T14:15:32+00:00

There's no reason for temparea to be static, since it's only used for
temporary sprintf output. It's not immediately obvious that the output
will always fit (in the worst case, the output including '\0' is
exactly 32 bytes), so save a future reader from worrying about that.

Signed-off-by: Rasmus Villemoes 
Signed-off-by: Jiri Kosina

block: add a bi_error field to struct bio

2015-07-29T14:55:15+00:00

Currently we have two different ways to signal an I/O error on a BIO:

 (1) by clearing the BIO_UPTODATE flag
 (2) by returning a Linux errno value to the bi_end_io callback

The first one has the drawback of only communicating a single possible
error (-EIO), and the second one has the drawback of not beeing persistent
when bios are queued up, and are not passed along from child to parent
bio in the ever more popular chaining scenario.  Having both mechanisms
available has the additional drawback of utterly confusing driver authors
and introducing bugs where various I/O submitters only deal with one of
them, and the others have to add boilerplate code to deal with both kinds
of error returns.

So add a new bi_error field to store an errno value directly in struct
bio and remove the existing mechanisms to clean all this up.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Hannes Reinecke 
Reviewed-by: NeilBrown 
Signed-off-by: Jens Axboe

floppy: Avoid manual call of device_create_file()

2015-02-03T12:00:36+00:00

Use the static attribute groups assigned to the device instead of
calling device_create_file() after the device registration.

Signed-off-by: Takashi Iwai 
Signed-off-by: Jiri Kosina

Merge branch 'for-jens' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/linux-block into for-linus

2014-06-18T17:30:22+00:00

floppy: format block0 read error message properly

2014-06-18T11:44:18+00:00

In case reading of block 0 fails, line without trailing newline
is printed causing dmesg to look horrible.

Signed-off-by: Jiri Kosina