Hello,
syzbot found the following issue on:
HEAD commit: dcc5c6f0 Merge tag 'x86-urgent-2020-08-30' of git://git.ke..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11e8ca85900000
kernel config: https://syzkaller.appspot.com/x/.config?x=891ca5711a9f1650
dashboard link: https://syzkaller.appspot.com/bug?extid=6448f3c229bc52b82f69
compiler: clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=154e2285900000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16f6e915900000
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email protected]
==================================================================
BUG: KASAN: use-after-free in kobject_put+0x245/0x2c0 lib/kobject.c:748
Read of size 1 at addr ffff8880a384e9bc by task syz-executor027/6982
CPU: 0 PID: 6982 Comm: syz-executor027 Not tainted 5.9.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1d6/0x29e lib/dump_stack.c:118
print_address_description+0x66/0x620 mm/kasan/report.c:383
__kasan_report mm/kasan/report.c:513 [inline]
kasan_report+0x132/0x1d0 mm/kasan/report.c:530
kobject_put+0x245/0x2c0 lib/kobject.c:748
delete_partition block/partitions/core.c:324 [inline]
bdev_del_partition+0x26a/0x380 block/partitions/core.c:549
blkpg_do_ioctl+0x12b/0x2e0 block/ioctl.c:33
blkpg_ioctl block/ioctl.c:69 [inline]
blkdev_ioctl+0x352/0x5d0 block/ioctl.c:589
block_ioctl+0xbc/0x100 fs/block_dev.c:1871
vfs_ioctl fs/ioctl.c:48 [inline]
__do_sys_ioctl fs/ioctl.c:753 [inline]
__se_sys_ioctl+0xfb/0x170 fs/ioctl.c:739
do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x446959
Code: e8 0c e8 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 db 06 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f4a7a555d98 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000006dbc38 RCX: 0000000000446959
RDX: 0000000020000000 RSI: 0000000000001269 RDI: 0000000000000005
RBP: 00000000006dbc30 R08: 00007f4a7a556700 R09: 0000000000000000
R10: 00007f4a7a556700 R11: 0000000000000246 R12: 00000000006dbc3c
R13: 00000000000000a9 R14: 00b747111e42e3ec R15: 02ba2b7a04b8ac00
Allocated by task 6977:
kasan_save_stack mm/kasan/common.c:48 [inline]
kasan_set_track mm/kasan/common.c:56 [inline]
__kasan_kmalloc+0x100/0x130 mm/kasan/common.c:461
kmem_cache_alloc_trace+0x1e4/0x2e0 mm/slab.c:3550
kmalloc include/linux/slab.h:554 [inline]
kzalloc include/linux/slab.h:666 [inline]
kobject_create lib/kobject.c:783 [inline]
kobject_create_and_add+0x57/0x240 lib/kobject.c:809
add_partition+0x884/0xcb0 block/partitions/core.c:443
bdev_add_partition+0x1c9/0x230 block/partitions/core.c:518
blkpg_do_ioctl+0x295/0x2e0 block/ioctl.c:52
blkpg_ioctl block/ioctl.c:69 [inline]
blkdev_ioctl+0x352/0x5d0 block/ioctl.c:589
block_ioctl+0xbc/0x100 fs/block_dev.c:1871
vfs_ioctl fs/ioctl.c:48 [inline]
__do_sys_ioctl fs/ioctl.c:753 [inline]
__se_sys_ioctl+0xfb/0x170 fs/ioctl.c:739
do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Freed by task 6979:
kasan_save_stack mm/kasan/common.c:48 [inline]
kasan_set_track+0x3d/0x70 mm/kasan/common.c:56
kasan_set_free_info+0x17/0x30 mm/kasan/generic.c:355
__kasan_slab_free+0xdd/0x110 mm/kasan/common.c:422
__cache_free mm/slab.c:3418 [inline]
kfree+0x113/0x200 mm/slab.c:3756
kobject_cleanup lib/kobject.c:704 [inline]
kobject_release lib/kobject.c:735 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x1a0/0x2c0 lib/kobject.c:752
delete_partition block/partitions/core.c:324 [inline]
bdev_del_partition+0x26a/0x380 block/partitions/core.c:549
blkpg_do_ioctl+0x12b/0x2e0 block/ioctl.c:33
blkpg_ioctl block/ioctl.c:69 [inline]
blkdev_ioctl+0x352/0x5d0 block/ioctl.c:589
block_ioctl+0xbc/0x100 fs/block_dev.c:1871
vfs_ioctl fs/ioctl.c:48 [inline]
__do_sys_ioctl fs/ioctl.c:753 [inline]
__se_sys_ioctl+0xfb/0x170 fs/ioctl.c:739
do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
The buggy address belongs to the object at ffff8880a384e980
which belongs to the cache kmalloc-64 of size 64
The buggy address is located 60 bytes inside of
64-byte region [ffff8880a384e980, ffff8880a384e9c0)
The buggy address belongs to the page:
page:00000000f601aef4 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0xa384e
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea000263b548 ffffea00029bbac8 ffff8880aa440200
raw: 0000000000000000 ffff8880a384e000 0000000100000020 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff8880a384e880: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
ffff8880a384e900: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
>ffff8880a384e980: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
^
ffff8880a384ea00: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
ffff8880a384ea80: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
==================================================================
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at [email protected].
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syzbot can test patches for this issue, for details see:
https://goo.gl/tpsmEJ#testing-patches
syzbot has bisected this issue to:
commit cddae808aeb77e5c29d22a8e0dfbdaed413f9e04
Author: Christoph Hellwig <[email protected]>
Date: Tue Apr 14 07:28:54 2020 +0000
block: pass a hd_struct to delete_partition
bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=17fa7656900000
start commit: dcc5c6f0 Merge tag 'x86-urgent-2020-08-30' of git://git.ke..
git tree: upstream
final oops: https://syzkaller.appspot.com/x/report.txt?x=14067656900000
console output: https://syzkaller.appspot.com/x/log.txt?x=10067656900000
kernel config: https://syzkaller.appspot.com/x/.config?x=891ca5711a9f1650
dashboard link: https://syzkaller.appspot.com/bug?extid=6448f3c229bc52b82f69
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=154e2285900000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16f6e915900000
Reported-by: [email protected]
Fixes: cddae808aeb7 ("block: pass a hd_struct to delete_partition")
For information about bisection process see: https://goo.gl/tpsmEJ#bisection
Hi all,
I have sent a patch which reverts cddae808aeb7 ("block: pass a
hd_struct to delete_partition") to syzbot, and it is now pending for
testing:
Link: https://groups.google.com/g/syzkaller-bugs/c/fnk0t9aqhDw/m/FO46-S8XAgAJ
Thank you,
Peilin Ye
In bdev_del_partition(), `part` is being looked up outside the critical
section. This is causing bdev_del_partition() to delete the same partition
more than once. Fix it by reverting commit cddae808aeb7.
Fixes: cddae808aeb7 ("block: pass a hd_struct to delete_partition")
Reported-and-tested-by: [email protected]
Cc: [email protected]
Cc: Hillf Danton <[email protected]>
Link: https://syzkaller.appspot.com/bug?id=09fc5ec437ea150f28e8a19f5011c08ee73381af
Signed-off-by: Peilin Ye <[email protected]>
---
block/blk.h | 2 +-
block/genhd.c | 2 +-
block/partitions/core.c | 22 ++++++++++++++--------
3 files changed, 16 insertions(+), 10 deletions(-)
diff --git a/block/blk.h b/block/blk.h
index 49e2928a1632..f5a46d0020fb 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -350,7 +350,7 @@ char *disk_name(struct gendisk *hd, int partno, char *buf);
#define ADDPART_FLAG_NONE 0
#define ADDPART_FLAG_RAID 1
#define ADDPART_FLAG_WHOLEDISK 2
-void delete_partition(struct gendisk *disk, struct hd_struct *part);
+void delete_partition(struct gendisk *disk, int partno);
int bdev_add_partition(struct block_device *bdev, int partno,
sector_t start, sector_t length);
int bdev_del_partition(struct block_device *bdev, int partno);
diff --git a/block/genhd.c b/block/genhd.c
index 99c64641c314..40abc70b92ab 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -913,7 +913,7 @@ void del_gendisk(struct gendisk *disk)
DISK_PITER_INCL_EMPTY | DISK_PITER_REVERSE);
while ((part = disk_part_iter_next(&piter))) {
invalidate_partition(disk, part->partno);
- delete_partition(disk, part);
+ delete_partition(disk, part->partno);
}
disk_part_iter_exit(&piter);
diff --git a/block/partitions/core.c b/block/partitions/core.c
index e62a98a8eeb7..1fe1fe593423 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -310,17 +310,25 @@ int hd_ref_init(struct hd_struct *part)
* Must be called either with bd_mutex held, before a disk can be opened or
* after all disk users are gone.
*/
-void delete_partition(struct gendisk *disk, struct hd_struct *part)
+void delete_partition(struct gendisk *disk, int partno)
{
struct disk_part_tbl *ptbl =
rcu_dereference_protected(disk->part_tbl, 1);
+ struct hd_struct *part;
+
+ if (partno >= ptbl->len)
+ return;
+
+ part = rcu_dereference_protected(ptbl->part[partno], 1);
+ if (!part)
+ return;
/*
* ->part_tbl is referenced in this part's release handler, so
* we have to hold the disk device
*/
get_device(disk_to_dev(part_to_disk(part)));
- rcu_assign_pointer(ptbl->part[part->partno], NULL);
+ rcu_assign_pointer(ptbl->part[partno], NULL);
kobject_put(part->holder_dir);
device_del(part_to_dev(part));
@@ -531,10 +539,10 @@ int bdev_del_partition(struct block_device *bdev, int partno)
if (!part)
return -ENXIO;
- ret = -ENOMEM;
bdevp = bdget(part_devt(part));
+ disk_put_part(part);
if (!bdevp)
- goto out_put_part;
+ return -ENOMEM;
mutex_lock(&bdevp->bd_mutex);
@@ -546,15 +554,13 @@ int bdev_del_partition(struct block_device *bdev, int partno)
invalidate_bdev(bdevp);
mutex_lock_nested(&bdev->bd_mutex, 1);
- delete_partition(bdev->bd_disk, part);
+ delete_partition(bdev->bd_disk, partno);
mutex_unlock(&bdev->bd_mutex);
ret = 0;
out_unlock:
mutex_unlock(&bdevp->bd_mutex);
bdput(bdevp);
-out_put_part:
- disk_put_part(part);
return ret;
}
@@ -627,7 +633,7 @@ int blk_drop_partitions(struct block_device *bdev)
disk_part_iter_init(&piter, bdev->bd_disk, DISK_PITER_INCL_EMPTY);
while ((part = disk_part_iter_next(&piter)))
- delete_partition(bdev->bd_disk, part);
+ delete_partition(bdev->bd_disk, part->partno);
disk_part_iter_exit(&piter);
return 0;
--
2.25.1
On Thu, Sep 03, 2020 at 02:55:34AM -0400, Peilin Ye wrote:
> In bdev_del_partition(), `part` is being looked up outside the critical
> section. This is causing bdev_del_partition() to delete the same partition
> more than once. Fix it by reverting commit cddae808aeb7.
We've already fix the problem properly:
https://git.kernel.dk/cgit/linux-block/commit/?h=block-5.9&id=08fc1ab6d748ab1a690fd483f41e2938984ce353
On Thu, Sep 03, 2020 at 08:59:50AM +0200, Christoph Hellwig wrote:
> On Thu, Sep 03, 2020 at 02:55:34AM -0400, Peilin Ye wrote:
> > In bdev_del_partition(), `part` is being looked up outside the critical
> > section. This is causing bdev_del_partition() to delete the same partition
> > more than once. Fix it by reverting commit cddae808aeb7.
>
> We've already fix the problem properly:
>
> https://git.kernel.dk/cgit/linux-block/commit/?h=block-5.9&id=08fc1ab6d748ab1a690fd483f41e2938984ce353
Ah, I searched linux-kernel but didn't see your patch, sorry about
that. I should have searched linux-block too.
Thank you,
Peilin