* Re: [syzbot] possible deadlock in attr_data_get_block
2022-10-17 7:43 [syzbot] possible deadlock in attr_data_get_block syzbot
@ 2022-12-04 18:11 ` syzbot
2024-06-19 6:52 ` [syzbot] fs/ntfs3: Do copy_to_user out of run_lock syzbot
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: syzbot @ 2022-12-04 18:11 UTC (permalink / raw)
To: almaz.alexandrovich, linux-kernel, ntfs3, syzkaller-bugs
syzbot has found a reproducer for the following issue on:
HEAD commit: c2bf05db6c78 Merge tag 'i2c-for-6.1-rc8' of git://git.kern..
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=1090bfbd880000
kernel config: https://syzkaller.appspot.com/x/.config?x=2325e409a9a893e1
dashboard link: https://syzkaller.appspot.com/bug?extid=36bb70085ef6edc2ebb9
compiler: Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1031c6cb880000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15392bd5880000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/4476d2eff1ae/disk-c2bf05db.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/0f4a704ffc14/vmlinux-c2bf05db.xz
kernel image: https://storage.googleapis.com/syzbot-assets/dfb09481a98b/bzImage-c2bf05db.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/9b8a62d1948c/mount_0.gz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+36bb70085ef6edc2ebb9@syzkaller.appspotmail.com
loop0: detected capacity change from 0 to 4096
======================================================
WARNING: possible circular locking dependency detected
6.1.0-rc7-syzkaller-00200-gc2bf05db6c78 #0 Not tainted
------------------------------------------------------
syz-executor598/3631 is trying to acquire lock:
ffff888072430860 (&ni->ni_lock/4){+.+.}-{3:3}, at: ni_lock fs/ntfs3/ntfs_fs.h:1108 [inline]
ffff888072430860 (&ni->ni_lock/4){+.+.}-{3:3}, at: attr_data_get_block+0x301/0x2370 fs/ntfs3/attrib.c:917
but task is already holding lock:
ffff888022a38898 (&mm->mmap_lock#2){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
ffff888022a38898 (&mm->mmap_lock#2){++++}-{3:3}, at: vm_mmap_pgoff+0x14d/0x2b0 mm/util.c:518
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (&mm->mmap_lock#2){++++}-{3:3}:
lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5668
__might_fault+0xb2/0x110 mm/memory.c:5645
_copy_to_user+0x26/0x130 lib/usercopy.c:29
copy_to_user include/linux/uaccess.h:169 [inline]
fiemap_fill_next_extent+0x22e/0x410 fs/ioctl.c:144
ni_fiemap+0xf57/0x1130 fs/ntfs3/frecord.c:1934
ntfs_fiemap+0x134/0x180 fs/ntfs3/file.c:1245
ioctl_fiemap fs/ioctl.c:219 [inline]
do_vfs_ioctl+0x187f/0x29a0 fs/ioctl.c:810
__do_sys_ioctl fs/ioctl.c:868 [inline]
__se_sys_ioctl+0x83/0x170 fs/ioctl.c:856
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
-> #0 (&ni->ni_lock/4){+.+.}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3097 [inline]
check_prevs_add kernel/locking/lockdep.c:3216 [inline]
validate_chain+0x1898/0x6ae0 kernel/locking/lockdep.c:3831
__lock_acquire+0x1292/0x1f60 kernel/locking/lockdep.c:5055
lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5668
__mutex_lock_common+0x1bd/0x26e0 kernel/locking/mutex.c:603
__mutex_lock kernel/locking/mutex.c:747 [inline]
mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:799
ni_lock fs/ntfs3/ntfs_fs.h:1108 [inline]
attr_data_get_block+0x301/0x2370 fs/ntfs3/attrib.c:917
ntfs_file_mmap+0x48c/0x730 fs/ntfs3/file.c:387
call_mmap include/linux/fs.h:2204 [inline]
mmap_region+0xfe6/0x1e20 mm/mmap.c:2625
do_mmap+0x8d9/0xf30 mm/mmap.c:1412
vm_mmap_pgoff+0x19e/0x2b0 mm/util.c:520
ksys_mmap_pgoff+0x48c/0x6d0 mm/mmap.c:1458
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&mm->mmap_lock#2);
lock(&ni->ni_lock/4);
lock(&mm->mmap_lock#2);
lock(&ni->ni_lock/4);
*** DEADLOCK ***
1 lock held by syz-executor598/3631:
#0: ffff888022a38898 (&mm->mmap_lock#2){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
#0: ffff888022a38898 (&mm->mmap_lock#2){++++}-{3:3}, at: vm_mmap_pgoff+0x14d/0x2b0 mm/util.c:518
stack backtrace:
CPU: 1 PID: 3631 Comm: syz-executor598 Not tainted 6.1.0-rc7-syzkaller-00200-gc2bf05db6c78 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1b1/0x28e lib/dump_stack.c:106
check_noncircular+0x2cc/0x390 kernel/locking/lockdep.c:2177
check_prev_add kernel/locking/lockdep.c:3097 [inline]
check_prevs_add kernel/locking/lockdep.c:3216 [inline]
validate_chain+0x1898/0x6ae0 kernel/locking/lockdep.c:3831
__lock_acquire+0x1292/0x1f60 kernel/locking/lockdep.c:5055
lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5668
__mutex_lock_common+0x1bd/0x26e0 kernel/locking/mutex.c:603
__mutex_lock kernel/locking/mutex.c:747 [inline]
mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:799
ni_lock fs/ntfs3/ntfs_fs.h:1108 [inline]
attr_data_get_block+0x301/0x2370 fs/ntfs3/attrib.c:917
ntfs_file_mmap+0x48c/0x730 fs/ntfs3/file.c:387
call_mmap include/linux/fs.h:2204 [inline]
mmap_region+0xfe6/0x1e20 mm/mmap.c:2625
do_mmap+0x8d9/0xf30 mm/mmap.c:1412
vm_mmap_pgoff+0x19e/0x2b0 mm/util.c:520
ksys_mmap_pgoff+0x48c/0x6d0 mm/mmap.c:1458
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f250307bcf9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 51 14 00 00 90 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 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [syzbot] fs/ntfs3: Do copy_to_user out of run_lock
2022-10-17 7:43 [syzbot] possible deadlock in attr_data_get_block syzbot
2022-12-04 18:11 ` syzbot
@ 2024-06-19 6:52 ` syzbot
2024-07-17 6:24 ` [syzbot] possible fix syzbot
2024-07-17 8:19 ` [syzbot] syzbot
3 siblings, 0 replies; 5+ messages in thread
From: syzbot @ 2024-06-19 6:52 UTC (permalink / raw)
To: linux-kernel, syzkaller-bugs
For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com.
***
Subject: fs/ntfs3: Do copy_to_user out of run_lock
Author: almaz.alexandrovich@paragon-software.com
#syz test
--- a/fs/ntfs3/frecord.c
+++ b/fs/ntfs3/frecord.c
@@ -1898,6 +1898,47 @@ enum REPARSE_SIGN ni_parse_reparse(struct
ntfs_inode *ni, struct ATTRIB *attr,
return REPARSE_LINK;
}
+/*
+ * fiemap_fill_next_extent_k - a copy of fiemap_fill_next_extent
+ * but it accepts kernel address for fi_extents_start
+ */
+static int fiemap_fill_next_extent_k(struct fiemap_extent_info *fieinfo,
+ u64 logical, u64 phys, u64 len, u32 flags)
+{
+ struct fiemap_extent extent;
+ struct fiemap_extent __user *dest = fieinfo->fi_extents_start;
+
+ /* only count the extents */
+ if (fieinfo->fi_extents_max == 0) {
+ fieinfo->fi_extents_mapped++;
+ return (flags & FIEMAP_EXTENT_LAST) ? 1 : 0;
+ }
+
+ if (fieinfo->fi_extents_mapped >= fieinfo->fi_extents_max)
+ return 1;
+
+ if (flags & FIEMAP_EXTENT_DELALLOC)
+ flags |= FIEMAP_EXTENT_UNKNOWN;
+ if (flags & FIEMAP_EXTENT_DATA_ENCRYPTED)
+ flags |= FIEMAP_EXTENT_ENCODED;
+ if (flags & (FIEMAP_EXTENT_DATA_TAIL | FIEMAP_EXTENT_DATA_INLINE))
+ flags |= FIEMAP_EXTENT_NOT_ALIGNED;
+
+ memset(&extent, 0, sizeof(extent));
+ extent.fe_logical = logical;
+ extent.fe_physical = phys;
+ extent.fe_length = len;
+ extent.fe_flags = flags;
+
+ dest += fieinfo->fi_extents_mapped;
+ memcpy(dest, &extent, sizeof(extent));
+
+ fieinfo->fi_extents_mapped++;
+ if (fieinfo->fi_extents_mapped == fieinfo->fi_extents_max)
+ return 1;
+ return (flags & FIEMAP_EXTENT_LAST) ? 1 : 0;
+}
+
/*
* ni_fiemap - Helper for file_fiemap().
*
@@ -1908,6 +1949,8 @@ int ni_fiemap(struct ntfs_inode *ni, struct
fiemap_extent_info *fieinfo,
__u64 vbo, __u64 len)
{
int err = 0;
+ struct fiemap_extent __user *fe_u = fieinfo->fi_extents_start;
+ struct fiemap_extent *fe_k = NULL;
struct ntfs_sb_info *sbi = ni->mi.sbi;
u8 cluster_bits = sbi->cluster_bits;
struct runs_tree *run;
@@ -1955,6 +1998,18 @@ int ni_fiemap(struct ntfs_inode *ni, struct
fiemap_extent_info *fieinfo,
goto out;
}
+ /*
+ * To avoid lock problems replace pointer to user memory by pointer
to kernel memory.
+ */
+ fe_k = kmalloc_array(fieinfo->fi_extents_max,
+ sizeof(struct fiemap_extent),
+ GFP_NOFS | __GFP_ZERO);
+ if (!fe_k) {
+ err = -ENOMEM;
+ goto out;
+ }
+ fieinfo->fi_extents_start = fe_k;
+
end = vbo + len;
alloc_size = le64_to_cpu(attr->nres.alloc_size);
if (end > alloc_size)
@@ -2043,8 +2098,9 @@ int ni_fiemap(struct ntfs_inode *ni, struct
fiemap_extent_info *fieinfo,
if (vbo + dlen >= end)
flags |= FIEMAP_EXTENT_LAST;
- err = fiemap_fill_next_extent(fieinfo, vbo, lbo, dlen,
- flags);
+ err = fiemap_fill_next_extent_k(fieinfo, vbo, lbo, dlen,
+ flags);
+
if (err < 0)
break;
if (err == 1) {
@@ -2064,7 +2120,8 @@ int ni_fiemap(struct ntfs_inode *ni, struct
fiemap_extent_info *fieinfo,
if (vbo + bytes >= end)
flags |= FIEMAP_EXTENT_LAST;
- err = fiemap_fill_next_extent(fieinfo, vbo, lbo, bytes, flags);
+ err = fiemap_fill_next_extent_k(fieinfo, vbo, lbo, bytes,
+ flags);
if (err < 0)
break;
if (err == 1) {
@@ -2077,7 +2134,19 @@ int ni_fiemap(struct ntfs_inode *ni, struct
fiemap_extent_info *fieinfo,
up_read(run_lock);
+ /*
+ * Copy to user memory out of lock
+ */
+ if (copy_to_user(fe_u, fe_k,
+ fieinfo->fi_extents_max *
+ sizeof(struct fiemap_extent))) {
+ err = -EFAULT;
+ }
+
out:
+ /* Restore original pointer. */
+ fieinfo->fi_extents_start = fe_u;
+ kfree(fe_k);
return err;
}
^ permalink raw reply [flat|nested] 5+ messages in thread