pps: Fix a use-after-free

On a board running ntpd and gpsd, I'm seeing a consistent use-after-free
in sys_exit() from gpsd when rebooting:

pps pps1: removed
------------[ cut here ]--------

pps: Fix a use-after-free

On a board running ntpd and gpsd, I'm seeing a consistent use-after-free
in sys_exit() from gpsd when rebooting:

pps pps1: removed
------------[ cut here ]------------
kobject: '(null)' (00000000db4bec24): is not initialized, yet kobject_put() is being called.
WARNING: CPU: 2 PID: 440 at lib/kobject.c:734 kobject_put+0x120/0x150
CPU: 2 UID: 299 PID: 440 Comm: gpsd Not tainted 6.11.0-rc6-00308-gb31c44928842 #1
Hardware name: Raspberry Pi 4 Model B Rev 1.1 (DT)
pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : kobject_put+0x120/0x150
lr : kobject_put+0x120/0x150
sp : ffffffc0803d3ae0
x29: ffffffc0803d3ae0 x28: ffffff8042dc9738 x27: 0000000000000001
x26: 0000000000000000 x25: ffffff8042dc9040 x24: ffffff8042dc9440
x23: ffffff80402a4620 x22: ffffff8042ef4bd0 x21: ffffff80405cb600
x20: 000000000008001b x19: ffffff8040b3b6e0 x18: 0000000000000000
x17: 0000000000000000 x16: 0000000000000000 x15: 696e6920746f6e20
x14: 7369203a29343263 x13: 205d303434542020 x12: 0000000000000000
x11: 0000000000000000 x10: 0000000000000000 x9 : 0000000000000000
x8 : 0000000000000000 x7 : 0000000000000000 x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000000000
x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000000
Call trace:
kobject_put+0x120/0x150
cdev_put+0x20/0x3c
__fput+0x2c4/0x2d8
____fput+0x1c/0x38
task_work_run+0x70/0xfc
do_exit+0x2a0/0x924
do_group_exit+0x34/0x90
get_signal+0x7fc/0x8c0
do_signal+0x128/0x13b4
do_notify_resume+0xdc/0x160
el0_svc+0xd4/0xf8
el0t_64_sync_handler+0x140/0x14c
el0t_64_sync+0x190/0x194
---[ end trace 0000000000000000 ]---

...followed by more symptoms of corruption, with similar stacks:

refcount_t: underflow; use-after-free.
kernel BUG at lib/list_debug.c:62!
Kernel panic - not syncing: Oops - BUG: Fatal exception

This happens because pps_device_destruct() frees the pps_device with the
embedded cdev immediately after calling cdev_del(), but, as the comment
above cdev_del() notes, fops for previously opened cdevs are still
callable even after cdev_del() returns. I think this bug has always
been there: I can't explain why it suddenly started happening every time
I reboot this particular board.

In commit d953e0e837e6 ("pps: Fix a use-after free bug when
unregistering a source."), George Spelvin suggested removing the
embedded cdev. That seems like the simplest way to fix this, so I've
implemented his suggestion, using __register_chrdev() with pps_idr
becoming the source of truth for which minor corresponds to which
device.

But now that pps_idr defines userspace visibility instead of cdev_add(),
we need to be sure the pps->dev refcount can't reach zero while
userspace can still find it again. So, the idr_remove() call moves to
pps_unregister_cdev(), and pps_idr now holds a reference to pps->dev.

pps_core: source serial1 got cdev (251:1)
<...>
pps pps1: removed
pps_core: unregistering pps1
pps_core: deallocating pps1

Fixes: d953e0e837e6 ("pps: Fix a use-after free bug when unregistering a source.")
Cc: [email protected]
Signed-off-by: Calvin Owens <[email protected]>
Reviewed-by: Michal Schmidt <[email protected]>
Link: https://lore.kernel.org/r/a17975fd5ae99385791929e563f72564edbcf28f.1731383727.git.calvin@wbinvd.org
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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[tree-wide] finally take no_llseek out

no_llseek had been defined to NULL two years ago, in commit 868941b14441
("fs: remove no_llseek")

To quote that commit,

At -rc1 we'll need do a mechanical

[tree-wide] finally take no_llseek out

no_llseek had been defined to NULL two years ago, in commit 868941b14441
("fs: remove no_llseek")

To quote that commit,

At -rc1 we'll need do a mechanical removal of no_llseek -

git grep -l -w no_llseek | grep -v porting.rst | while read i; do
sed -i '/\<no_llseek\>/d' $i
done

would do it.

Unfortunately, that hadn't been done. Linus, could you do that now, so
that we could finally put that thing to rest? All instances are of the
form
.llseek = no_llseek,
so it's obviously safe.

Signed-off-by: Al Viro <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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driver core: class: remove module * from class_create()

The module pointer in class_create() never actually did anything, and it
shouldn't have been requred to be set as a parameter even if it did
s

driver core: class: remove module * from class_create()

The module pointer in class_create() never actually did anything, and it
shouldn't have been requred to be set as a parameter even if it did
something. So just remove it and fix up all callers of the function in
the kernel tree at the same time.

Cc: "Rafael J. Wysocki" <[email protected]>
Acked-by: Benjamin Tissoires <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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drivers/pps/pps.c: clear offset flags in PPS_SETPARAMS ioctl

The PPS assert/clear offset corrections are set by the PPS_SETPARAMS
ioctl in the pps_ktime structs, which also contain flags. The flags

drivers/pps/pps.c: clear offset flags in PPS_SETPARAMS ioctl

The PPS assert/clear offset corrections are set by the PPS_SETPARAMS
ioctl in the pps_ktime structs, which also contain flags. The flags are
not initialized by applications (using the timepps.h header) and they
are not used by the kernel for anything except returning them back in
the PPS_GETPARAMS ioctl.

Set the flags to zero to make it clear they are unused and avoid leaking
uninitialized data of the PPS_SETPARAMS caller to other applications
that have a read access to the PPS device.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Miroslav Lichvar <[email protected]>
Reviewed-by: Thomas Gleixner <[email protected]>
Acked-by: Rodolfo Giometti <[email protected]>
Cc: Greg KH <[email protected]>
Cc: Dan Carpenter <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 61

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 61

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version this program is distributed in the
hope that it will be useful but without any warranty without even
the implied warranty of merchantability or fitness for a particular
purpose see the gnu general public license for more details you
should have received a copy of the gnu general public license along
with this program if not write to the free software foundation inc
675 mass ave cambridge ma 02139 usa

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 441 file(s).

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Michael Ellerman <[email protected]> (powerpc)
Reviewed-by: Richard Fontana <[email protected]>
Reviewed-by: Allison Randal <[email protected]>
Reviewed-by: Kate Stewart <[email protected]>
Cc: [email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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vfs: do bulk POLL* -> EPOLL* replacement

This is the mindless scripted replacement of kernel use of POLL*
variables as described by Al, done by this script:

for V in IN OUT PRI ERR RDNORM RDBAN

vfs: do bulk POLL* -> EPOLL* replacement

This is the mindless scripted replacement of kernel use of POLL*
variables as described by Al, done by this script:

for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do
L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'`
for f in $L; do sed -i "-es/^\([^\"]*\)\(\<POLL$V\>\)/\\1E\\2/" $f; done
done

with de-mangling cleanups yet to come.

NOTE! On almost all architectures, the EPOLL* constants have the same
values as the POLL* constants do. But they keyword here is "almost".
For various bad reasons they aren't the same, and epoll() doesn't
actually work quite correctly in some cases due to this on Sparc et al.

The next patch from Al will sort out the final differences, and we
should be all done.

Scripted-by: Al Viro <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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the rest of drivers/*: annotate ->poll() instances

Signed-off-by: Al Viro <[email protected]>

pps: fix padding issue with PPS_FETCH for ioctl_compat

Issue is that x86 32-bit aligns to 4-bytes instead of 8-bytes
so this patchset works around the issue and corrects the data
returned in pps_fda

pps: fix padding issue with PPS_FETCH for ioctl_compat

Issue is that x86 32-bit aligns to 4-bytes instead of 8-bytes
so this patchset works around the issue and corrects the data
returned in pps_fdata_compat.

Acked-by: Rodolfo Giometti <[email protected]>
Signed-off-by: Matt Ranostay <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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pps: add ioctl_compat function to correct ioctl definitions

ioctl definitions use the pointer size of the architecture which
is fine when userspace and kernel are the same bitsize. This
patchset wor

pps: add ioctl_compat function to correct ioctl definitions

ioctl definitions use the pointer size of the architecture which
is fine when userspace and kernel are the same bitsize. This
patchset workarounds an issue with mixed bitsize kernel + userspace
by rewriting the cmd to the kernelspace architecture pointer size.

Acked-by: Rodolfo Giometti <[email protected]>
Signed-off-by: Matt Ranostay <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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PPS: convert class code to use dev_groups

The dev_attrs field of struct class is going away soon, dev_groups
should be used instead. This converts the pps class code to use the
correct field.

Cc:

PPS: convert class code to use dev_groups

The dev_attrs field of struct class is going away soon, dev_groups
should be used instead. This converts the pps class code to use the
correct field.

Cc: Rodolfo Giometti <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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pps: convert to idr_alloc()

Convert to the much saner new idr interface.

Signed-off-by: Tejun Heo <[email protected]>
Cc: Rodolfo Giometti <[email protected]>
Signed-off-by: Andrew Morton <akpm@lin

pps: convert to idr_alloc()

Convert to the much saner new idr interface.

Signed-off-by: Tejun Heo <[email protected]>
Cc: Rodolfo Giometti <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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pps: Fix a use-after free bug when unregistering a source.

Remove the cdev from the system (with cdev_del) *before* deallocating it
(in pps_device_destruct, called via kobject_put from device_destro

pps: Fix a use-after free bug when unregistering a source.

Remove the cdev from the system (with cdev_del) *before* deallocating it
(in pps_device_destruct, called via kobject_put from device_destroy).

Also prevent deallocating a device with open file handles.

A better long-term fix is probably to remove the cdev from the pps_device
entirely, and instead have all devices reference one global cdev. Then
the deallocation ordering becomes simpler.

But that's more complex and invasive change, so we leave that
for later.

Signed-off-by: George Spelvin <[email protected]>
Cc: stable <[email protected]>
Acked-by: Rodolfo Giometti <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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pps: Add pps_lookup_dev() function

The PPS serial line discipline wants to attach a PPS device to a tty
without changing the tty code to add a struct pps_device * pointer.

Since the number of PPS d

pps: Add pps_lookup_dev() function

The PPS serial line discipline wants to attach a PPS device to a tty
without changing the tty code to add a struct pps_device * pointer.

Since the number of PPS devices in a typical system is generally very low
(n=1 is by far the most common), it's practical to search the entire list
of allocated pps devices. (We capture the timestamp before the lookup,
so the timing isn't affected.)

It is a bit ugly that this function, which is part of the in-kernel
PPS API, has to be in pps.c as opposed to kapi,c, but that's not
something that affects users.

Signed-off-by: George Spelvin <[email protected]>
Acked-by: Rodolfo Giometti <[email protected]>
Cc: stable <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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idr: rename MAX_LEVEL to MAX_IDR_LEVEL

To avoid name conflicts:

drivers/video/riva/fbdev.c:281:9: sparse: preprocessor token MAX_LEVEL redefined

While at it, also make the other names more consi

idr: rename MAX_LEVEL to MAX_IDR_LEVEL

To avoid name conflicts:

drivers/video/riva/fbdev.c:281:9: sparse: preprocessor token MAX_LEVEL redefined

While at it, also make the other names more consistent and add
parentheses.

[[email protected]: repair fallout]
[[email protected]: IB/mlx4: fix for MAX_ID_MASK to MAX_IDR_MASK name change]
Signed-off-by: Fengguang Wu <[email protected]>
Cc: Bernd Petrovitsch <[email protected]>
Cc: walter harms <[email protected]>
Cc: Glauber Costa <[email protected]>
Signed-off-by: Stephen Rothwell <[email protected]>
Cc: Roland Dreier <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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pps: return PTR_ERR on error in device_create

We should return PTR_ERR if the call to the device_create function fails.
Without this patch we instead return the value from a successful call to
cdev_

pps: return PTR_ERR on error in device_create

We should return PTR_ERR if the call to the device_create function fails.
Without this patch we instead return the value from a successful call to
cdev_add if the call to device_create fails.

Signed-off-by: Emil Goode <[email protected]>
Acked-by: Devendra Naga <[email protected]>
Cc: Alexander Gordeev <[email protected]>
Cc: Rodolfo Giometti <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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pps: class_create() returns an ERR_PTR, not NULL

class_create() never returns NULLs only ERR_PTRs.

Signed-off-by: Dan Carpenter <[email protected]>
Cc: Rodolfo Giometti <[email protected]

pps: class_create() returns an ERR_PTR, not NULL

class_create() never returns NULLs only ERR_PTRs.

Signed-off-by: Dan Carpenter <[email protected]>
Cc: Rodolfo Giometti <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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pps: add kernel consumer support

Add an optional feature of PPSAPI, kernel consumer support, which uses the
added hardpps() function.

Signed-off-by: Alexander Gordeev <[email protected]>
Acked-

pps: add kernel consumer support

Add an optional feature of PPSAPI, kernel consumer support, which uses the
added hardpps() function.

Signed-off-by: Alexander Gordeev <[email protected]>
Acked-by: Rodolfo Giometti <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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pps: make idr lock a mutex and protect idr_pre_get

Now pps_idr_lock is never used in interrupt context so we can replace
spin_lock_irq/spin_unlock_irq with plain spin_lock/spin_unlock. But
there is

pps: make idr lock a mutex and protect idr_pre_get

Now pps_idr_lock is never used in interrupt context so we can replace
spin_lock_irq/spin_unlock_irq with plain spin_lock/spin_unlock. But
there is also a potential race condition when someone can steal an id
which was allocated by idr_pre_get before it is used. So convert spin
lock to mutex and protect the whole id generation process.

Signed-off-by: Alexander Gordeev <[email protected]>
Cc: Rodolfo Giometti <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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pps: move idr stuff to pps.c

Since now idr is only used to manage char device id's and not used in
kernel API anymore it should be moved to pps.c. This also makes it
possible to release id only at

pps: move idr stuff to pps.c

Since now idr is only used to manage char device id's and not used in
kernel API anymore it should be moved to pps.c. This also makes it
possible to release id only at actual device freeing so nobody can
register a pps device with the same id while our device is not freed yet.

Signed-off-by: Alexander Gordeev <[email protected]>
Acked-by: Rodolfo Giometti <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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pps: convert printk/pr_* to dev_*

Since we now have direct pointers to struct pps_device everywhere it's
easy to use dev_* functions to print messages instead of plain printks.
Where dev_* cannot be

pps: convert printk/pr_* to dev_*

Since we now have direct pointers to struct pps_device everywhere it's
easy to use dev_* functions to print messages instead of plain printks.
Where dev_* cannot be used printks are converted to pr_*.

Signed-off-by: Alexander Gordeev <[email protected]>
Acked-by: Rodolfo Giometti <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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pps: access pps device by direct pointer

Using device index as a pointer needs some unnecessary work to be done
every time the pointer is needed (in irq handler for example). Using a
direct pointer

pps: access pps device by direct pointer

Using device index as a pointer needs some unnecessary work to be done
every time the pointer is needed (in irq handler for example). Using a
direct pointer is much more easy (and safe as well).

Signed-off-by: Alexander Gordeev <[email protected]>
Acked-by: Rodolfo Giometti <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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pps: fix race in PPS_FETCH handler

There was a race in PPS_FETCH ioctl handler when several processes want to
obtain PPS data simultaneously using sleeping PPS_FETCH. They all sleep
most of the tim

pps: fix race in PPS_FETCH handler

There was a race in PPS_FETCH ioctl handler when several processes want to
obtain PPS data simultaneously using sleeping PPS_FETCH. They all sleep
most of the time in the system call.

With the old approach when the first process waiting on the pps queue is
waken up it makes new system call right away and zeroes pps->go. So other
processes continue to sleep. This is a clear race condition because of
the global 'go' variable.

With the new approach pps->last_ev holds some value increasing at each PPS
event. PPS_FETCH ioctl handler saves current value to the local variable
at the very beginning so it can safely check that there is a new event by
just comparing both variables.

Signed-off-by: Alexander Gordeev <[email protected]>
Acked-by: Rodolfo Giometti <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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pps: declare variables where they are used in switch

Move variable declarations where they are used in pps_cdev_ioctl.

Signed-off-by: Alexander Gordeev <[email protected]>
Acked-by: Rodolfo Gio

pps: declare variables where they are used in switch

Move variable declarations where they are used in pps_cdev_ioctl.

Signed-off-by: Alexander Gordeev <[email protected]>
Acked-by: Rodolfo Giometti <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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pps: locking scheme fix up for PPS_GETPARAMS

Userland programs may read/write PPS parameters at same time and these
operations may corrupt PPS data.

Signed-off-by: Rodolfo Giometti <giometti@linux.

pps: locking scheme fix up for PPS_GETPARAMS

Userland programs may read/write PPS parameters at same time and these
operations may corrupt PPS data.

Signed-off-by: Rodolfo Giometti <[email protected]>
Tested-by: Reg Clemens <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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pps: fix incorrect verdict check

Fix incorrect verdict check and returns error if device_create failed,
otherwise driver triggers kernel oops.

Signed-off-by: Joonwoo Park<[email protected]>
Cc:

pps: fix incorrect verdict check

Fix incorrect verdict check and returns error if device_create failed,
otherwise driver triggers kernel oops.

Signed-off-by: Joonwoo Park<[email protected]>
Cc: Rodolfo Giometti <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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