commit 77da160530dd1dc94f6ae15a981f24e5f0021e84 upstream.
I got a KASAN report of use-after-free:
==================================================================
BUG: KASAN: use-after-free in klist_iter_exit+0x61/0x70 at addr ffff8800b6581508
Read of size 8 by task trinity-c1/315
=============================================================================
BUG kmalloc-32 (Not tainted): kasan: bad access detected
-----------------------------------------------------------------------------
Disabling lock debugging due to kernel taint
INFO: Allocated in disk_seqf_start+0x66/0x110 age=144 cpu=1 pid=315
___slab_alloc+0x4f1/0x520
__slab_alloc.isra.58+0x56/0x80
kmem_cache_alloc_trace+0x260/0x2a0
disk_seqf_start+0x66/0x110
traverse+0x176/0x860
seq_read+0x7e3/0x11a0
proc_reg_read+0xbc/0x180
do_loop_readv_writev+0x134/0x210
do_readv_writev+0x565/0x660
vfs_readv+0x67/0xa0
do_preadv+0x126/0x170
SyS_preadv+0xc/0x10
do_syscall_64+0x1a1/0x460
return_from_SYSCALL_64+0x0/0x6a
INFO: Freed in disk_seqf_stop+0x42/0x50 age=160 cpu=1 pid=315
__slab_free+0x17a/0x2c0
kfree+0x20a/0x220
disk_seqf_stop+0x42/0x50
traverse+0x3b5/0x860
seq_read+0x7e3/0x11a0
proc_reg_read+0xbc/0x180
do_loop_readv_writev+0x134/0x210
do_readv_writev+0x565/0x660
vfs_readv+0x67/0xa0
do_preadv+0x126/0x170
SyS_preadv+0xc/0x10
do_syscall_64+0x1a1/0x460
return_from_SYSCALL_64+0x0/0x6a
CPU: 1 PID: 315 Comm: trinity-c1 Tainted: G B 4.7.0+ #62
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
ffffea0002d96000 ffff880119b9f918 ffffffff81d6ce81 ffff88011a804480
ffff8800b6581500 ffff880119b9f948 ffffffff8146c7bd ffff88011a804480
ffffea0002d96000 ffff8800b6581500 fffffffffffffff4 ffff880119b9f970
Call Trace:
[<ffffffff81d6ce81>] dump_stack+0x65/0x84
[<ffffffff8146c7bd>] print_trailer+0x10d/0x1a0
[<ffffffff814704ff>] object_err+0x2f/0x40
[<ffffffff814754d1>] kasan_report_error+0x221/0x520
[<ffffffff8147590e>] __asan_report_load8_noabort+0x3e/0x40
[<ffffffff83888161>] klist_iter_exit+0x61/0x70
[<ffffffff82404389>] class_dev_iter_exit+0x9/0x10
[<ffffffff81d2e8ea>] disk_seqf_stop+0x3a/0x50
[<ffffffff8151f812>] seq_read+0x4b2/0x11a0
[<ffffffff815f8fdc>] proc_reg_read+0xbc/0x180
[<ffffffff814b24e4>] do_loop_readv_writev+0x134/0x210
[<ffffffff814b4c45>] do_readv_writev+0x565/0x660
[<ffffffff814b8a17>] vfs_readv+0x67/0xa0
[<ffffffff814b8de6>] do_preadv+0x126/0x170
[<ffffffff814b92ec>] SyS_preadv+0xc/0x10
This problem can occur in the following situation:
open()
- pread()
- .seq_start()
- iter = kmalloc() // succeeds
- seqf->private = iter
- .seq_stop()
- kfree(seqf->private)
- pread()
- .seq_start()
- iter = kmalloc() // fails
- .seq_stop()
- class_dev_iter_exit(seqf->private) // boom! old pointer
As the comment in disk_seqf_stop() says, stop is called even if start
failed, so we need to reinitialise the private pointer to NULL when seq
iteration stops.
An alternative would be to set the private pointer to NULL when the
kmalloc() in disk_seqf_start() fails.
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 8ba8682107ee2ca3347354e018865d8e1967c5f4 upstream.
get_task_ioprio() accesses the task->io_context without holding the task
lock and thus can race with exit_io_context(), leading to a
use-after-free. The reproducer below hits this within a few seconds on
my 4-core QEMU VM:
#define _GNU_SOURCE
#include <assert.h>
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/wait.h>
int main(int argc, char **argv)
{
pid_t pid, child;
long nproc, i;
/* ioprio_set(IOPRIO_WHO_PROCESS, 0, IOPRIO_PRIO_VALUE(IOPRIO_CLASS_IDLE, 0)); */
syscall(SYS_ioprio_set, 1, 0, 0x6000);
nproc = sysconf(_SC_NPROCESSORS_ONLN);
for (i = 0; i < nproc; i++) {
pid = fork();
assert(pid != -1);
if (pid == 0) {
for (;;) {
pid = fork();
assert(pid != -1);
if (pid == 0) {
_exit(0);
} else {
child = wait(NULL);
assert(child == pid);
}
}
}
pid = fork();
assert(pid != -1);
if (pid == 0) {
for (;;) {
/* ioprio_get(IOPRIO_WHO_PGRP, 0); */
syscall(SYS_ioprio_get, 2, 0);
}
}
}
for (;;) {
/* ioprio_get(IOPRIO_WHO_PGRP, 0); */
syscall(SYS_ioprio_get, 2, 0);
}
return 0;
}
This gets us KASAN dumps like this:
[ 35.526914] ==================================================================
[ 35.530009] BUG: KASAN: out-of-bounds in get_task_ioprio+0x7b/0x90 at addr ffff880066f34e6c
[ 35.530009] Read of size 2 by task ioprio-gpf/363
[ 35.530009] =============================================================================
[ 35.530009] BUG blkdev_ioc (Not tainted): kasan: bad access detected
[ 35.530009] -----------------------------------------------------------------------------
[ 35.530009] Disabling lock debugging due to kernel taint
[ 35.530009] INFO: Allocated in create_task_io_context+0x2b/0x370 age=0 cpu=0 pid=360
[ 35.530009] ___slab_alloc+0x55d/0x5a0
[ 35.530009] __slab_alloc.isra.20+0x2b/0x40
[ 35.530009] kmem_cache_alloc_node+0x84/0x200
[ 35.530009] create_task_io_context+0x2b/0x370
[ 35.530009] get_task_io_context+0x92/0xb0
[ 35.530009] copy_process.part.8+0x5029/0x5660
[ 35.530009] _do_fork+0x155/0x7e0
[ 35.530009] SyS_clone+0x19/0x20
[ 35.530009] do_syscall_64+0x195/0x3a0
[ 35.530009] return_from_SYSCALL_64+0x0/0x6a
[ 35.530009] INFO: Freed in put_io_context+0xe7/0x120 age=0 cpu=0 pid=1060
[ 35.530009] __slab_free+0x27b/0x3d0
[ 35.530009] kmem_cache_free+0x1fb/0x220
[ 35.530009] put_io_context+0xe7/0x120
[ 35.530009] put_io_context_active+0x238/0x380
[ 35.530009] exit_io_context+0x66/0x80
[ 35.530009] do_exit+0x158e/0x2b90
[ 35.530009] do_group_exit+0xe5/0x2b0
[ 35.530009] SyS_exit_group+0x1d/0x20
[ 35.530009] entry_SYSCALL_64_fastpath+0x1a/0xa4
[ 35.530009] INFO: Slab 0xffffea00019bcd00 objects=20 used=4 fp=0xffff880066f34ff0 flags=0x1fffe0000004080
[ 35.530009] INFO: Object 0xffff880066f34e58 @offset=3672 fp=0x0000000000000001
[ 35.530009] ==================================================================
Fix it by grabbing the task lock while we poke at the io_context.
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull block fixes from Jens Axboe:
"A few fixes for the current series. This contains:
- Two fixes for NVMe:
One fixes a reset race that can be triggered by repeated
insert/removal of the module.
The other fixes an issue on some platforms, where we get probe
timeouts since legacy interrupts isn't working. This used not to
be a problem since we had the worker thread poll for completions,
but since that was killed off, it means those poor souls can't
successfully probe their NVMe device. Use a proper IRQ check and
probe (msi-x -> msi ->legacy), like most other drivers to work
around this. Both from Keith.
- A loop corruption issue with offset in iters, from Ming Lei.
- A fix for not having the partition stat per cpu ref count
initialized before sending out the KOBJ_ADD, which could cause user
space to access the counter prior to initialization. Also from
Ming Lei.
- A fix for using the wrong congestion state, from Kaixu Xia"
* 'for-linus' of git://git.kernel.dk/linux-block:
block: loop: fix filesystem corruption in case of aio/dio
NVMe: Always use MSI/MSI-x interrupts
NVMe: Fix reset/remove race
writeback: fix the wrong congested state variable definition
block: partition: initialize percpuref before sending out KOBJ_ADD
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Mostly direct substitution with occasional adjustment or removing outdated comments. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time
ago with promise that one day it will be possible to implement page
cache with bigger chunks than PAGE_SIZE.
This promise never materialized. And unlikely will.
We have many places where PAGE_CACHE_SIZE assumed to be equal to
PAGE_SIZE. And it's constant source of confusion on whether
PAGE_CACHE_* or PAGE_* constant should be used in a particular case,
especially on the border between fs and mm.
Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much
breakage to be doable.
Let's stop pretending that pages in page cache are special. They are
not.
The changes are pretty straight-forward:
- <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;
- <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;
- PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN};
- page_cache_get() -> get_page();
- page_cache_release() -> put_page();
This patch contains automated changes generated with coccinelle using
script below. For some reason, coccinelle doesn't patch header files.
I've called spatch for them manually.
The only adjustment after coccinelle is revert of changes to
PAGE_CAHCE_ALIGN definition: we are going to drop it later.
There are few places in the code where coccinelle didn't reach. I'll
fix them manually in a separate patch. Comments and documentation also
will be addressed with the separate patch.
virtual patch
@@
expression E;
@@
- E << (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E
@@
expression E;
@@
- E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E
@@
@@
- PAGE_CACHE_SHIFT
+ PAGE_SHIFT
@@
@@
- PAGE_CACHE_SIZE
+ PAGE_SIZE
@@
@@
- PAGE_CACHE_MASK
+ PAGE_MASK
@@
expression E;
@@
- PAGE_CACHE_ALIGN(E)
+ PAGE_ALIGN(E)
@@
expression E;
@@
- page_cache_get(E)
+ get_page(E)
@@
expression E;
@@
- page_cache_release(E)
+ put_page(E)
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The initialization of partition's percpu_ref should have been done before sending out KOBJ_ADD uevent, which may cause userspace to read partition table. So the uninitialized percpu_ref may be accessed in data path. This patch fixes this issue reported by Naveen. Reported-by: Naveen Kaje <nkaje@codeaurora.org> Tested-by: Naveen Kaje <nkaje@codeaurora.org> Fixes: 6c71013ecb7e2(block: partition: convert percpu ref) Cc: <stable@vger.kernel.org> # v4.3+ Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Pull block fixes from Jens Axboe:
"Final round of fixes for this merge window - some of this has come up
after the initial pull request, and some of it was put in a post-merge
branch before the merge window.
This contains:
- Fix for a bad check for an error on dma mapping in the mtip32xx
driver, from Alexey Khoroshilov.
- A set of fixes for lightnvm, from Javier, Matias, and Wenwei.
- An NVMe completion record corruption fix from Marta, ensuring that
we read things in the right order.
- Two writeback fixes from Tejun, marked for stable@ as well.
- A blk-mq sw queue iterator fix from Thomas, fixing an oops for
sparse CPU maps. They hit this in the hot plug/unplug rework"
* 'for-linus' of git://git.kernel.dk/linux-block:
nvme: avoid cqe corruption when update at the same time as read
writeback, cgroup: fix use of the wrong bdi_writeback which mismatches the inode
writeback, cgroup: fix premature wb_put() in locked_inode_to_wb_and_lock_list()
blk-mq: Use proper cpumask iterator
mtip32xx: fix checks for dma mapping errors
lightnvm: do not load L2P table if not supported
lightnvm: do not reserve lun on l2p loading
nvme: lightnvm: return ppa completion status
lightnvm: add a bitmap of luns
lightnvm: specify target's logical address area
null_blk: add lightnvm null_blk device to the nullb_list
queue_for_each_ctx() iterates over per_cpu variables under the assumption that the possible cpu mask cannot have holes. That's wrong as all cpumasks can have holes. In case there are holes the iteration ends up accessing uninitialized memory and crashing as a result. Replace the macro by a proper for_each_possible_cpu() loop and drop the unused macro blk_ctx_sum() which references queue_for_each_ctx(). Reported-by: Xiong Zhou <jencce.kernel@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Jens Axboe <axboe@fb.com>