Re: [syzbot] [dri?] BUG: sleeping function called from invalid context in _vm_unmap_aliases

2023-03-22 Thread Tetsuo Handa
Commit c53e98934f93 ("mm: vmalloc: use rwsem, mutex for vmap_area_lock and 
vmap_block->lock")
is broken. We can't take mutex (a sleeping lock) inside RCU read section (an 
atomic context).


@@ -2183,7 +2184,7 @@ static void _vm_unmap_aliases(unsigned long start, 
unsigned long end, int flush)

rcu_read_lock();
list_for_each_entry_rcu(vb, >free, free_list) {
-   spin_lock(>lock);
+   mutex_lock(>lock);
if (vb->dirty && vb->dirty != VMAP_BBMAP_BITS) {
unsigned long va_start = vb->va->va_start;
unsigned long s, e;
@@ -2196,7 +2197,7 @@ static void _vm_unmap_aliases(unsigned long start, 
unsigned long end, int flush)

flush = 1;
}
-   spin_unlock(>lock);
+   mutex_unlock(>lock);
}
rcu_read_unlock();
}

#syz set subsystems: mm

On 2023/03/22 2:04, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:f3594f0204b7 Add linux-next specific files for 20230321
> git tree:   linux-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=161552eec8
> kernel config:  https://syzkaller.appspot.com/x/.config?x=f22105589e896af1
> dashboard link: https://syzkaller.appspot.com/bug?extid=a9a2bb6afe9eb31efc56
> compiler:   gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils 
> for Debian) 2.35.2
> 
> Unfortunately, I don't have any reproducer for this issue yet.
> 
> Downloadable assets:
> disk image: 
> https://storage.googleapis.com/syzbot-assets/0b755145006a/disk-f3594f02.raw.xz
> vmlinux: 
> https://storage.googleapis.com/syzbot-assets/fca26e328a81/vmlinux-f3594f02.xz
> kernel image: 
> https://storage.googleapis.com/syzbot-assets/39744d7d289f/bzImage-f3594f02.xz
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+a9a2bb6afe9eb31ef...@syzkaller.appspotmail.com
> 



[syzbot] [dri?] BUG: sleeping function called from invalid context in _vm_unmap_aliases

2023-03-21 Thread syzbot
Hello,

syzbot found the following issue on:

HEAD commit:f3594f0204b7 Add linux-next specific files for 20230321
git tree:   linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=161552eec8
kernel config:  https://syzkaller.appspot.com/x/.config?x=f22105589e896af1
dashboard link: https://syzkaller.appspot.com/bug?extid=a9a2bb6afe9eb31efc56
compiler:   gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for 
Debian) 2.35.2

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: 
https://storage.googleapis.com/syzbot-assets/0b755145006a/disk-f3594f02.raw.xz
vmlinux: 
https://storage.googleapis.com/syzbot-assets/fca26e328a81/vmlinux-f3594f02.xz
kernel image: 
https://storage.googleapis.com/syzbot-assets/39744d7d289f/bzImage-f3594f02.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a9a2bb6afe9eb31ef...@syzkaller.appspotmail.com

BUG: sleeping function called from invalid context at kernel/locking/mutex.c:580
in_atomic(): 0, irqs_disabled(): 0, non_block: 0, pid: 10028, name: 
syz-executor.4
preempt_count: 0, expected: 0
RCU nest depth: 1, expected: 0
3 locks held by syz-executor.4/10028:
 #0: 88807597afd8 (>mmap_lock){}-{3:3}, at: 
mmap_write_lock_killable include/linux/mmap_lock.h:110 [inline]
 #0: 88807597afd8 (>mmap_lock){}-{3:3}, at: 
vm_mmap_pgoff+0x158/0x3b0 mm/util.c:541
 #1: 888081123270 (>pages_lock){+.+.}-{3:3}, at: 
drm_gem_shmem_get_pages+0x53/0x180 drivers/gpu/drm/drm_gem_shmem_helper.c:216
 #2: 8c796500 (rcu_read_lock){}-{1:2}, at: 
_vm_unmap_aliases.part.0+0x138/0x560 mm/vmalloc.c:2182
CPU: 1 PID: 10028 Comm: syz-executor.4 Not tainted 
6.3.0-rc3-next-20230321-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 
03/02/2023
Call Trace:
 
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x136/0x150 lib/dump_stack.c:106
 __might_resched+0x358/0x580 kernel/sched/core.c:10059
 __mutex_lock_common kernel/locking/mutex.c:580 [inline]
 __mutex_lock+0x9f/0x1350 kernel/locking/mutex.c:747
 _vm_unmap_aliases.part.0+0x1ca/0x560 mm/vmalloc.c:2187
 _vm_unmap_aliases mm/vmalloc.c:2181 [inline]
 vm_unmap_aliases+0x49/0x50 mm/vmalloc.c:2230
 change_page_attr_set_clr+0x226/0x470 arch/x86/mm/pat/set_memory.c:1837
 cpa_set_pages_array arch/x86/mm/pat/set_memory.c:1892 [inline]
 _set_pages_array+0x1c6/0x220 arch/x86/mm/pat/set_memory.c:2230
 drm_gem_shmem_get_pages_locked+0x155/0x240 
drivers/gpu/drm/drm_gem_shmem_helper.c:191
 drm_gem_shmem_get_pages+0x71/0x180 drivers/gpu/drm/drm_gem_shmem_helper.c:219
 drm_gem_shmem_mmap drivers/gpu/drm/drm_gem_shmem_helper.c:636 [inline]
 drm_gem_shmem_mmap+0x153/0x540 drivers/gpu/drm/drm_gem_shmem_helper.c:620
 drm_gem_mmap_obj+0x1b6/0x6c0 drivers/gpu/drm/drm_gem.c:1046
 drm_gem_mmap+0x41d/0x780 drivers/gpu/drm/drm_gem.c:1124
 call_mmap include/linux/fs.h:1859 [inline]
 mmap_region+0x694/0x28d0 mm/mmap.c:2652
 do_mmap+0x831/0xf60 mm/mmap.c:1438
 vm_mmap_pgoff+0x1a2/0x3b0 mm/util.c:543
 ksys_mmap_pgoff+0x41f/0x5a0 mm/mmap.c:1484
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f905968c0f9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:7f905a3fa168 EFLAGS: 0246 ORIG_RAX: 0009
RAX: ffda RBX: 7f90597abf80 RCX: 7f905968c0f9
RDX:  RSI: 3028 RDI: 20ffc000
RBP: 7f90596e7b39 R08: 0004 R09: 0001
R10: 0012 R11: 0246 R12: 
R13: 7ffcde03503f R14: 7f905a3fa300 R15: 00022000
 

=
[ BUG: Invalid wait context ]
6.3.0-rc3-next-20230321-syzkaller #0 Tainted: GW 
-
syz-executor.4/10028 is trying to lock:
888027c7a068 (>lock){+.+.}-{3:3}, at: 
_vm_unmap_aliases.part.0+0x1ca/0x560 mm/vmalloc.c:2187
other info that might help us debug this:
context-{4:4}
3 locks held by syz-executor.4/10028:
 #0: 88807597afd8 (>mmap_lock){}-{3:3}, at: 
mmap_write_lock_killable include/linux/mmap_lock.h:110 [inline]
 #0: 88807597afd8 (>mmap_lock){}-{3:3}, at: 
vm_mmap_pgoff+0x158/0x3b0 mm/util.c:541
 #1: 888081123270 (>pages_lock){+.+.}-{3:3}, at: 
drm_gem_shmem_get_pages+0x53/0x180 drivers/gpu/drm/drm_gem_shmem_helper.c:216
 #2: 8c796500 (rcu_read_lock){}-{1:2}, at: 
_vm_unmap_aliases.part.0+0x138/0x560 mm/vmalloc.c:2182
stack backtrace:
CPU: 1 PID: 10028 Comm: syz-executor.4 Tainted: GW  
6.3.0-rc3-next-20230321-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 
03/02/2023
Call Trace:
 
 __dump_stack