* [syzbot] possible deadlock in tty_port_tty_get
@ 2022-09-30 22:05 syzbot
2022-10-03 8:44 ` Ilpo Järvinen
2023-03-25 23:02 ` [syzbot] [serial?] possible deadlock in tty_port_tty_get syzbot
0 siblings, 2 replies; 4+ messages in thread
From: syzbot @ 2022-09-30 22:05 UTC (permalink / raw)
To: andy.shevchenko, etremblay, gregkh, ilpo.jarvinen, jirislaby,
linux-kernel, linux-serial, syzkaller-bugs, u.kleine-koenig,
wander
Hello,
syzbot found the following issue on:
HEAD commit: 5a77386984b5 Merge tag 'drm-fixes-2022-09-30-1' of git://a..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=132b8504880000
kernel config: https://syzkaller.appspot.com/x/.config?x=a1992c90769e07
dashboard link: https://syzkaller.appspot.com/bug?extid=223c7461c58c58a4cb10
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.
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+223c7461c58c58a4cb10@syzkaller.appspotmail.com
======================================================
WARNING: possible circular locking dependency detected
6.0.0-rc7-syzkaller-00162-g5a77386984b5 #0 Not tainted
------------------------------------------------------
syz-executor.0/4926 is trying to acquire lock:
ffffffff8c0be788 (zonelist_update_seq.seqcount){...-}-{0:0}, at: __alloc_pages+0x43d/0x510 mm/page_alloc.c:5562
but task is already holding lock:
ffff88802624c958 (&port->lock){-.-.}-{2:2}, at: tty_insert_flip_string_and_push_buffer+0x2b/0x160 drivers/tty/tty_buffer.c:628
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #3 (&port->lock){-.-.}-{2:2}:
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x39/0x50 kernel/locking/spinlock.c:162
tty_port_tty_get+0x1f/0x100 drivers/tty/tty_port.c:327
tty_port_default_wakeup+0x11/0x40 drivers/tty/tty_port.c:68
serial8250_tx_chars+0x4f6/0xd90 drivers/tty/serial/8250/8250_port.c:1851
serial8250_handle_irq.part.0+0x440/0x820 drivers/tty/serial/8250/8250_port.c:1938
serial8250_handle_irq drivers/tty/serial/8250/8250_port.c:1911 [inline]
serial8250_default_handle_irq+0xb2/0x220 drivers/tty/serial/8250/8250_port.c:1958
serial8250_interrupt+0xf8/0x200 drivers/tty/serial/8250/8250_core.c:126
__handle_irq_event_percpu+0x227/0x870 kernel/irq/handle.c:158
handle_irq_event_percpu kernel/irq/handle.c:193 [inline]
handle_irq_event+0xa7/0x1e0 kernel/irq/handle.c:210
handle_edge_irq+0x25f/0xd00 kernel/irq/chip.c:819
generic_handle_irq_desc include/linux/irqdesc.h:158 [inline]
handle_irq arch/x86/kernel/irq.c:231 [inline]
__common_interrupt+0x9d/0x210 arch/x86/kernel/irq.c:250
common_interrupt+0xa4/0xc0 arch/x86/kernel/irq.c:240
asm_common_interrupt+0x22/0x40 arch/x86/include/asm/idtentry.h:640
native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
default_idle+0xb/0x10 arch/x86/kernel/process.c:730
default_idle_call+0x80/0xc0 kernel/sched/idle.c:109
cpuidle_idle_call kernel/sched/idle.c:191 [inline]
do_idle+0x401/0x590 kernel/sched/idle.c:303
cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:400
start_secondary+0x21d/0x2b0 arch/x86/kernel/smpboot.c:262
secondary_startup_64_no_verify+0xce/0xdb
-> #2 (&port_lock_key){-.-.}-{2:2}:
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x39/0x50 kernel/locking/spinlock.c:162
serial8250_console_write+0x975/0xfe0 drivers/tty/serial/8250/8250_port.c:3380
call_console_driver kernel/printk/printk.c:1945 [inline]
console_emit_next_record.constprop.0+0x3de/0x840 kernel/printk/printk.c:2732
console_flush_all kernel/printk/printk.c:2794 [inline]
console_unlock+0x37a/0x5a0 kernel/printk/printk.c:2861
vprintk_emit+0x1b9/0x5f0 kernel/printk/printk.c:2271
vprintk+0x80/0x90 kernel/printk/printk_safe.c:50
_printk+0xba/0xed kernel/printk/printk.c:2292
register_console kernel/printk/printk.c:3212 [inline]
register_console+0x482/0x840 kernel/printk/printk.c:3104
univ8250_console_init+0x3a/0x46 drivers/tty/serial/8250/8250_core.c:681
console_init+0x3b7/0x57e kernel/printk/printk.c:3308
start_kernel+0x2fa/0x48f init/main.c:1066
secondary_startup_64_no_verify+0xce/0xdb
-> #1 (console_owner){-...}-{0:0}:
console_lock_spinning_enable kernel/printk/printk.c:1808 [inline]
console_emit_next_record.constprop.0+0x2dd/0x840 kernel/printk/printk.c:2729
console_flush_all kernel/printk/printk.c:2794 [inline]
console_unlock+0x37a/0x5a0 kernel/printk/printk.c:2861
vprintk_emit+0x1b9/0x5f0 kernel/printk/printk.c:2271
vprintk+0x80/0x90 kernel/printk/printk_safe.c:50
_printk+0xba/0xed kernel/printk/printk.c:2292
build_zonelists.cold+0xe5/0x11f mm/page_alloc.c:6471
__build_all_zonelists+0x111/0x180 mm/page_alloc.c:6584
build_all_zonelists_init+0x2f/0x104 mm/page_alloc.c:6609
build_all_zonelists+0x11f/0x140 mm/page_alloc.c:6642
start_kernel+0xb9/0x48f init/main.c:960
secondary_startup_64_no_verify+0xce/0xdb
-> #0 (zonelist_update_seq.seqcount){...-}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3095 [inline]
check_prevs_add kernel/locking/lockdep.c:3214 [inline]
validate_chain kernel/locking/lockdep.c:3829 [inline]
__lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5053
lock_acquire kernel/locking/lockdep.c:5666 [inline]
lock_acquire+0x1ab/0x570 kernel/locking/lockdep.c:5631
seqcount_lockdep_reader_access include/linux/seqlock.h:102 [inline]
read_seqbegin include/linux/seqlock.h:836 [inline]
zonelist_iter_begin mm/page_alloc.c:4722 [inline]
__alloc_pages_slowpath.constprop.0+0x1a5/0x2300 mm/page_alloc.c:5044
__alloc_pages+0x43d/0x510 mm/page_alloc.c:5562
__alloc_pages_node include/linux/gfp.h:243 [inline]
kmem_getpages mm/slab.c:1363 [inline]
cache_grow_begin+0x75/0x360 mm/slab.c:2569
cache_alloc_refill+0x27f/0x380 mm/slab.c:2942
____cache_alloc mm/slab.c:3018 [inline]
____cache_alloc mm/slab.c:3001 [inline]
__do_cache_alloc mm/slab.c:3246 [inline]
slab_alloc mm/slab.c:3287 [inline]
__do_kmalloc mm/slab.c:3684 [inline]
__kmalloc+0x3a1/0x4a0 mm/slab.c:3695
kmalloc include/linux/slab.h:605 [inline]
tty_buffer_alloc+0x27b/0x2f0 drivers/tty/tty_buffer.c:180
__tty_buffer_request_room+0x15f/0x2b0 drivers/tty/tty_buffer.c:278
tty_insert_flip_string_fixed_flag+0x8c/0x250 drivers/tty/tty_buffer.c:327
tty_insert_flip_string include/linux/tty_flip.h:41 [inline]
tty_insert_flip_string_and_push_buffer+0x3e/0x160 drivers/tty/tty_buffer.c:629
pty_write+0xd6/0x100 drivers/tty/pty.c:118
process_output_block drivers/tty/n_tty.c:586 [inline]
n_tty_write+0x4ca/0xfd0 drivers/tty/n_tty.c:2350
do_tty_write drivers/tty/tty_io.c:1024 [inline]
file_tty_write.constprop.0+0x499/0x8f0 drivers/tty/tty_io.c:1095
call_write_iter include/linux/fs.h:2187 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x9e9/0xdd0 fs/read_write.c:584
ksys_write+0x127/0x250 fs/read_write.c:637
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
other info that might help us debug this:
Chain exists of:
zonelist_update_seq.seqcount --> &port_lock_key --> &port->lock
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&port->lock);
lock(&port_lock_key);
lock(&port->lock);
lock(zonelist_update_seq.seqcount);
*** DEADLOCK ***
5 locks held by syz-executor.0/4926:
#0: ffff88806b3c3098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:244
#1: ffff88806b3c3130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: tty_write_lock drivers/tty/tty_io.c:950 [inline]
#1: ffff88806b3c3130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: do_tty_write drivers/tty/tty_io.c:973 [inline]
#1: ffff88806b3c3130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: file_tty_write.constprop.0+0x296/0x8f0 drivers/tty/tty_io.c:1095
#2: ffff88806b3c32e8 (&o_tty->termios_rwsem/1){++++}-{3:3}, at: n_tty_write+0x1bf/0xfd0 drivers/tty/n_tty.c:2333
#3: ffffc90000cf4380 (&ldata->output_lock){+.+.}-{3:3}, at: process_output_block drivers/tty/n_tty.c:541 [inline]
#3: ffffc90000cf4380 (&ldata->output_lock){+.+.}-{3:3}, at: n_tty_write+0x5f6/0xfd0 drivers/tty/n_tty.c:2350
#4: ffff88802624c958 (&port->lock){-.-.}-{2:2}, at: tty_insert_flip_string_and_push_buffer+0x2b/0x160 drivers/tty/tty_buffer.c:628
stack backtrace:
CPU: 1 PID: 4926 Comm: syz-executor.0 Not tainted 6.0.0-rc7-syzkaller-00162-g5a77386984b5 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2175
check_prev_add kernel/locking/lockdep.c:3095 [inline]
check_prevs_add kernel/locking/lockdep.c:3214 [inline]
validate_chain kernel/locking/lockdep.c:3829 [inline]
__lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5053
lock_acquire kernel/locking/lockdep.c:5666 [inline]
lock_acquire+0x1ab/0x570 kernel/locking/lockdep.c:5631
seqcount_lockdep_reader_access include/linux/seqlock.h:102 [inline]
read_seqbegin include/linux/seqlock.h:836 [inline]
zonelist_iter_begin mm/page_alloc.c:4722 [inline]
__alloc_pages_slowpath.constprop.0+0x1a5/0x2300 mm/page_alloc.c:5044
__alloc_pages+0x43d/0x510 mm/page_alloc.c:5562
__alloc_pages_node include/linux/gfp.h:243 [inline]
kmem_getpages mm/slab.c:1363 [inline]
cache_grow_begin+0x75/0x360 mm/slab.c:2569
cache_alloc_refill+0x27f/0x380 mm/slab.c:2942
____cache_alloc mm/slab.c:3018 [inline]
____cache_alloc mm/slab.c:3001 [inline]
__do_cache_alloc mm/slab.c:3246 [inline]
slab_alloc mm/slab.c:3287 [inline]
__do_kmalloc mm/slab.c:3684 [inline]
__kmalloc+0x3a1/0x4a0 mm/slab.c:3695
kmalloc include/linux/slab.h:605 [inline]
tty_buffer_alloc+0x27b/0x2f0 drivers/tty/tty_buffer.c:180
__tty_buffer_request_room+0x15f/0x2b0 drivers/tty/tty_buffer.c:278
tty_insert_flip_string_fixed_flag+0x8c/0x250 drivers/tty/tty_buffer.c:327
tty_insert_flip_string include/linux/tty_flip.h:41 [inline]
tty_insert_flip_string_and_push_buffer+0x3e/0x160 drivers/tty/tty_buffer.c:629
pty_write+0xd6/0x100 drivers/tty/pty.c:118
process_output_block drivers/tty/n_tty.c:586 [inline]
n_tty_write+0x4ca/0xfd0 drivers/tty/n_tty.c:2350
do_tty_write drivers/tty/tty_io.c:1024 [inline]
file_tty_write.constprop.0+0x499/0x8f0 drivers/tty/tty_io.c:1095
call_write_iter include/linux/fs.h:2187 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x9e9/0xdd0 fs/read_write.c:584
ksys_write+0x127/0x250 fs/read_write.c:637
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7feffde8a5a9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007feffcdfe168 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007feffdfabf80 RCX: 00007feffde8a5a9
RDX: 00000000fffffedf RSI: 0000000020000000 RDI: 0000000000000004
RBP: 00007feffdee5580 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fffc3837d3f R14: 00007feffcdfe300 R15: 0000000000022000
</TASK>
---
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 syzkaller@googlegroups.com.
syzbot will keep track of this issue. See:
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [syzbot] possible deadlock in tty_port_tty_get
2022-09-30 22:05 [syzbot] possible deadlock in tty_port_tty_get syzbot
@ 2022-10-03 8:44 ` Ilpo Järvinen
2023-04-02 10:48 ` [PATCH] mm/page_alloc: don't check zonelist_update_seq from atomic allocations Tetsuo Handa
2023-03-25 23:02 ` [syzbot] [serial?] possible deadlock in tty_port_tty_get syzbot
1 sibling, 1 reply; 4+ messages in thread
From: Ilpo Järvinen @ 2022-10-03 8:44 UTC (permalink / raw)
To: syzbot
Cc: andy.shevchenko, etremblay, Greg Kroah-Hartman, Jiri Slaby, LKML,
linux-serial, syzkaller-bugs, u.kleine-koenig, wander, Mel Gorman
+ Cc Mel Gorman.
--
i.
On Fri, 30 Sep 2022, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: 5a77386984b5 Merge tag 'drm-fixes-2022-09-30-1' of git://a..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=132b8504880000
> kernel config: https://syzkaller.appspot.com/x/.config?x=a1992c90769e07
> dashboard link: https://syzkaller.appspot.com/bug?extid=223c7461c58c58a4cb10
> 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.
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+223c7461c58c58a4cb10@syzkaller.appspotmail.com
>
> ======================================================
> WARNING: possible circular locking dependency detected
> 6.0.0-rc7-syzkaller-00162-g5a77386984b5 #0 Not tainted
> ------------------------------------------------------
> syz-executor.0/4926 is trying to acquire lock:
> ffffffff8c0be788 (zonelist_update_seq.seqcount){...-}-{0:0}, at: __alloc_pages+0x43d/0x510 mm/page_alloc.c:5562
>
> but task is already holding lock:
> ffff88802624c958 (&port->lock){-.-.}-{2:2}, at: tty_insert_flip_string_and_push_buffer+0x2b/0x160 drivers/tty/tty_buffer.c:628
>
> which lock already depends on the new lock.
>
>
> the existing dependency chain (in reverse order) is:
>
> -> #3 (&port->lock){-.-.}-{2:2}:
> __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
> _raw_spin_lock_irqsave+0x39/0x50 kernel/locking/spinlock.c:162
> tty_port_tty_get+0x1f/0x100 drivers/tty/tty_port.c:327
> tty_port_default_wakeup+0x11/0x40 drivers/tty/tty_port.c:68
> serial8250_tx_chars+0x4f6/0xd90 drivers/tty/serial/8250/8250_port.c:1851
> serial8250_handle_irq.part.0+0x440/0x820 drivers/tty/serial/8250/8250_port.c:1938
> serial8250_handle_irq drivers/tty/serial/8250/8250_port.c:1911 [inline]
> serial8250_default_handle_irq+0xb2/0x220 drivers/tty/serial/8250/8250_port.c:1958
> serial8250_interrupt+0xf8/0x200 drivers/tty/serial/8250/8250_core.c:126
> __handle_irq_event_percpu+0x227/0x870 kernel/irq/handle.c:158
> handle_irq_event_percpu kernel/irq/handle.c:193 [inline]
> handle_irq_event+0xa7/0x1e0 kernel/irq/handle.c:210
> handle_edge_irq+0x25f/0xd00 kernel/irq/chip.c:819
> generic_handle_irq_desc include/linux/irqdesc.h:158 [inline]
> handle_irq arch/x86/kernel/irq.c:231 [inline]
> __common_interrupt+0x9d/0x210 arch/x86/kernel/irq.c:250
> common_interrupt+0xa4/0xc0 arch/x86/kernel/irq.c:240
> asm_common_interrupt+0x22/0x40 arch/x86/include/asm/idtentry.h:640
> native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
> arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
> default_idle+0xb/0x10 arch/x86/kernel/process.c:730
> default_idle_call+0x80/0xc0 kernel/sched/idle.c:109
> cpuidle_idle_call kernel/sched/idle.c:191 [inline]
> do_idle+0x401/0x590 kernel/sched/idle.c:303
> cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:400
> start_secondary+0x21d/0x2b0 arch/x86/kernel/smpboot.c:262
> secondary_startup_64_no_verify+0xce/0xdb
>
> -> #2 (&port_lock_key){-.-.}-{2:2}:
> __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
> _raw_spin_lock_irqsave+0x39/0x50 kernel/locking/spinlock.c:162
> serial8250_console_write+0x975/0xfe0 drivers/tty/serial/8250/8250_port.c:3380
> call_console_driver kernel/printk/printk.c:1945 [inline]
> console_emit_next_record.constprop.0+0x3de/0x840 kernel/printk/printk.c:2732
> console_flush_all kernel/printk/printk.c:2794 [inline]
> console_unlock+0x37a/0x5a0 kernel/printk/printk.c:2861
> vprintk_emit+0x1b9/0x5f0 kernel/printk/printk.c:2271
> vprintk+0x80/0x90 kernel/printk/printk_safe.c:50
> _printk+0xba/0xed kernel/printk/printk.c:2292
> register_console kernel/printk/printk.c:3212 [inline]
> register_console+0x482/0x840 kernel/printk/printk.c:3104
> univ8250_console_init+0x3a/0x46 drivers/tty/serial/8250/8250_core.c:681
> console_init+0x3b7/0x57e kernel/printk/printk.c:3308
> start_kernel+0x2fa/0x48f init/main.c:1066
> secondary_startup_64_no_verify+0xce/0xdb
>
> -> #1 (console_owner){-...}-{0:0}:
> console_lock_spinning_enable kernel/printk/printk.c:1808 [inline]
> console_emit_next_record.constprop.0+0x2dd/0x840 kernel/printk/printk.c:2729
> console_flush_all kernel/printk/printk.c:2794 [inline]
> console_unlock+0x37a/0x5a0 kernel/printk/printk.c:2861
> vprintk_emit+0x1b9/0x5f0 kernel/printk/printk.c:2271
> vprintk+0x80/0x90 kernel/printk/printk_safe.c:50
> _printk+0xba/0xed kernel/printk/printk.c:2292
> build_zonelists.cold+0xe5/0x11f mm/page_alloc.c:6471
> __build_all_zonelists+0x111/0x180 mm/page_alloc.c:6584
> build_all_zonelists_init+0x2f/0x104 mm/page_alloc.c:6609
> build_all_zonelists+0x11f/0x140 mm/page_alloc.c:6642
> start_kernel+0xb9/0x48f init/main.c:960
> secondary_startup_64_no_verify+0xce/0xdb
>
> -> #0 (zonelist_update_seq.seqcount){...-}-{0:0}:
> check_prev_add kernel/locking/lockdep.c:3095 [inline]
> check_prevs_add kernel/locking/lockdep.c:3214 [inline]
> validate_chain kernel/locking/lockdep.c:3829 [inline]
> __lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5053
> lock_acquire kernel/locking/lockdep.c:5666 [inline]
> lock_acquire+0x1ab/0x570 kernel/locking/lockdep.c:5631
> seqcount_lockdep_reader_access include/linux/seqlock.h:102 [inline]
> read_seqbegin include/linux/seqlock.h:836 [inline]
> zonelist_iter_begin mm/page_alloc.c:4722 [inline]
> __alloc_pages_slowpath.constprop.0+0x1a5/0x2300 mm/page_alloc.c:5044
> __alloc_pages+0x43d/0x510 mm/page_alloc.c:5562
> __alloc_pages_node include/linux/gfp.h:243 [inline]
> kmem_getpages mm/slab.c:1363 [inline]
> cache_grow_begin+0x75/0x360 mm/slab.c:2569
> cache_alloc_refill+0x27f/0x380 mm/slab.c:2942
> ____cache_alloc mm/slab.c:3018 [inline]
> ____cache_alloc mm/slab.c:3001 [inline]
> __do_cache_alloc mm/slab.c:3246 [inline]
> slab_alloc mm/slab.c:3287 [inline]
> __do_kmalloc mm/slab.c:3684 [inline]
> __kmalloc+0x3a1/0x4a0 mm/slab.c:3695
> kmalloc include/linux/slab.h:605 [inline]
> tty_buffer_alloc+0x27b/0x2f0 drivers/tty/tty_buffer.c:180
> __tty_buffer_request_room+0x15f/0x2b0 drivers/tty/tty_buffer.c:278
> tty_insert_flip_string_fixed_flag+0x8c/0x250 drivers/tty/tty_buffer.c:327
> tty_insert_flip_string include/linux/tty_flip.h:41 [inline]
> tty_insert_flip_string_and_push_buffer+0x3e/0x160 drivers/tty/tty_buffer.c:629
> pty_write+0xd6/0x100 drivers/tty/pty.c:118
> process_output_block drivers/tty/n_tty.c:586 [inline]
> n_tty_write+0x4ca/0xfd0 drivers/tty/n_tty.c:2350
> do_tty_write drivers/tty/tty_io.c:1024 [inline]
> file_tty_write.constprop.0+0x499/0x8f0 drivers/tty/tty_io.c:1095
> call_write_iter include/linux/fs.h:2187 [inline]
> new_sync_write fs/read_write.c:491 [inline]
> vfs_write+0x9e9/0xdd0 fs/read_write.c:584
> ksys_write+0x127/0x250 fs/read_write.c:637
> do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
> entry_SYSCALL_64_after_hwframe+0x63/0xcd
>
> other info that might help us debug this:
>
> Chain exists of:
> zonelist_update_seq.seqcount --> &port_lock_key --> &port->lock
>
> Possible unsafe locking scenario:
>
> CPU0 CPU1
> ---- ----
> lock(&port->lock);
> lock(&port_lock_key);
> lock(&port->lock);
> lock(zonelist_update_seq.seqcount);
>
> *** DEADLOCK ***
>
> 5 locks held by syz-executor.0/4926:
> #0: ffff88806b3c3098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:244
> #1: ffff88806b3c3130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: tty_write_lock drivers/tty/tty_io.c:950 [inline]
> #1: ffff88806b3c3130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: do_tty_write drivers/tty/tty_io.c:973 [inline]
> #1: ffff88806b3c3130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: file_tty_write.constprop.0+0x296/0x8f0 drivers/tty/tty_io.c:1095
> #2: ffff88806b3c32e8 (&o_tty->termios_rwsem/1){++++}-{3:3}, at: n_tty_write+0x1bf/0xfd0 drivers/tty/n_tty.c:2333
> #3: ffffc90000cf4380 (&ldata->output_lock){+.+.}-{3:3}, at: process_output_block drivers/tty/n_tty.c:541 [inline]
> #3: ffffc90000cf4380 (&ldata->output_lock){+.+.}-{3:3}, at: n_tty_write+0x5f6/0xfd0 drivers/tty/n_tty.c:2350
> #4: ffff88802624c958 (&port->lock){-.-.}-{2:2}, at: tty_insert_flip_string_and_push_buffer+0x2b/0x160 drivers/tty/tty_buffer.c:628
>
> stack backtrace:
> CPU: 1 PID: 4926 Comm: syz-executor.0 Not tainted 6.0.0-rc7-syzkaller-00162-g5a77386984b5 #0
> Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
> Call Trace:
> <TASK>
> __dump_stack lib/dump_stack.c:88 [inline]
> dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
> check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2175
> check_prev_add kernel/locking/lockdep.c:3095 [inline]
> check_prevs_add kernel/locking/lockdep.c:3214 [inline]
> validate_chain kernel/locking/lockdep.c:3829 [inline]
> __lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5053
> lock_acquire kernel/locking/lockdep.c:5666 [inline]
> lock_acquire+0x1ab/0x570 kernel/locking/lockdep.c:5631
> seqcount_lockdep_reader_access include/linux/seqlock.h:102 [inline]
> read_seqbegin include/linux/seqlock.h:836 [inline]
> zonelist_iter_begin mm/page_alloc.c:4722 [inline]
> __alloc_pages_slowpath.constprop.0+0x1a5/0x2300 mm/page_alloc.c:5044
> __alloc_pages+0x43d/0x510 mm/page_alloc.c:5562
> __alloc_pages_node include/linux/gfp.h:243 [inline]
> kmem_getpages mm/slab.c:1363 [inline]
> cache_grow_begin+0x75/0x360 mm/slab.c:2569
> cache_alloc_refill+0x27f/0x380 mm/slab.c:2942
> ____cache_alloc mm/slab.c:3018 [inline]
> ____cache_alloc mm/slab.c:3001 [inline]
> __do_cache_alloc mm/slab.c:3246 [inline]
> slab_alloc mm/slab.c:3287 [inline]
> __do_kmalloc mm/slab.c:3684 [inline]
> __kmalloc+0x3a1/0x4a0 mm/slab.c:3695
> kmalloc include/linux/slab.h:605 [inline]
> tty_buffer_alloc+0x27b/0x2f0 drivers/tty/tty_buffer.c:180
> __tty_buffer_request_room+0x15f/0x2b0 drivers/tty/tty_buffer.c:278
> tty_insert_flip_string_fixed_flag+0x8c/0x250 drivers/tty/tty_buffer.c:327
> tty_insert_flip_string include/linux/tty_flip.h:41 [inline]
> tty_insert_flip_string_and_push_buffer+0x3e/0x160 drivers/tty/tty_buffer.c:629
> pty_write+0xd6/0x100 drivers/tty/pty.c:118
> process_output_block drivers/tty/n_tty.c:586 [inline]
> n_tty_write+0x4ca/0xfd0 drivers/tty/n_tty.c:2350
> do_tty_write drivers/tty/tty_io.c:1024 [inline]
> file_tty_write.constprop.0+0x499/0x8f0 drivers/tty/tty_io.c:1095
> call_write_iter include/linux/fs.h:2187 [inline]
> new_sync_write fs/read_write.c:491 [inline]
> vfs_write+0x9e9/0xdd0 fs/read_write.c:584
> ksys_write+0x127/0x250 fs/read_write.c:637
> do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
> entry_SYSCALL_64_after_hwframe+0x63/0xcd
> RIP: 0033:0x7feffde8a5a9
> Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007feffcdfe168 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
> RAX: ffffffffffffffda RBX: 00007feffdfabf80 RCX: 00007feffde8a5a9
> RDX: 00000000fffffedf RSI: 0000000020000000 RDI: 0000000000000004
> RBP: 00007feffdee5580 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 00007fffc3837d3f R14: 00007feffcdfe300 R15: 0000000000022000
> </TASK>
>
>
> ---
> 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 syzkaller@googlegroups.com.
>
> syzbot will keep track of this issue. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [syzbot] [serial?] possible deadlock in tty_port_tty_get
2022-09-30 22:05 [syzbot] possible deadlock in tty_port_tty_get syzbot
2022-10-03 8:44 ` Ilpo Järvinen
@ 2023-03-25 23:02 ` syzbot
1 sibling, 0 replies; 4+ messages in thread
From: syzbot @ 2023-03-25 23:02 UTC (permalink / raw)
To: andy.shevchenko, etremblay, gregkh, ilpo.jarvinen, jirislaby,
linux-kernel, linux-serial, syzkaller-bugs, u.kleine-koenig,
wander
syzbot has found a reproducer for the following issue on:
HEAD commit: 65aca32efdcb Merge tag 'mm-hotfixes-stable-2023-03-24-17-0..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17b21b0ec80000
kernel config: https://syzkaller.appspot.com/x/.config?x=8ef27c4ff127cda5
dashboard link: https://syzkaller.appspot.com/bug?extid=223c7461c58c58a4cb10
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1591ba51c80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12ac6789c80000
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+223c7461c58c58a4cb10@syzkaller.appspotmail.com
======================================================
WARNING: possible circular locking dependency detected
6.3.0-rc3-syzkaller-00317-g65aca32efdcb #0 Not tainted
------------------------------------------------------
syz-executor930/5168 is trying to acquire lock:
ffffffff8c8e11e8 (zonelist_update_seq.seqcount){...-}-{0:0}, at: __alloc_pages+0x408/0x4a0 mm/page_alloc.c:5605
but task is already holding lock:
ffff888014325958 (&port->lock){-...}-{2:2}, at: tty_insert_flip_string_and_push_buffer+0x2f/0x160 drivers/tty/tty_buffer.c:628
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #3 (&port->lock){-...}-{2:2}:
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x3d/0x60 kernel/locking/spinlock.c:162
tty_port_tty_get+0x21/0xf0 drivers/tty/tty_port.c:327
tty_port_default_wakeup+0x15/0x40 drivers/tty/tty_port.c:68
serial8250_tx_chars+0x53e/0xdf0 drivers/tty/serial/8250/8250_port.c:1865
serial8250_handle_irq.part.0+0x460/0x870 drivers/tty/serial/8250/8250_port.c:1955
serial8250_handle_irq drivers/tty/serial/8250/8250_port.c:1928 [inline]
serial8250_default_handle_irq+0xb6/0x230 drivers/tty/serial/8250/8250_port.c:1975
serial8250_interrupt+0xfc/0x200 drivers/tty/serial/8250/8250_core.c:127
__handle_irq_event_percpu+0x22b/0x730 kernel/irq/handle.c:158
handle_irq_event_percpu kernel/irq/handle.c:193 [inline]
handle_irq_event+0xab/0x1e0 kernel/irq/handle.c:210
handle_edge_irq+0x263/0xd00 kernel/irq/chip.c:819
generic_handle_irq_desc include/linux/irqdesc.h:158 [inline]
handle_irq arch/x86/kernel/irq.c:231 [inline]
__common_interrupt+0xa1/0x220 arch/x86/kernel/irq.c:250
common_interrupt+0xa8/0xd0 arch/x86/kernel/irq.c:240
asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:636
native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline]
arch_safe_halt arch/x86/include/asm/irqflags.h:86 [inline]
default_idle+0xf/0x20 arch/x86/kernel/process.c:703
default_idle_call+0x67/0xa0 kernel/sched/idle.c:97
cpuidle_idle_call kernel/sched/idle.c:170 [inline]
do_idle+0x31e/0x3e0 kernel/sched/idle.c:282
cpu_startup_entry+0x18/0x20 kernel/sched/idle.c:379
start_secondary+0x221/0x2b0 arch/x86/kernel/smpboot.c:264
secondary_startup_64_no_verify+0xce/0xdb
-> #2 (&port_lock_key
){-...}-{2:2}:
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x3d/0x60 kernel/locking/spinlock.c:162
serial8250_console_write+0x4ba/0x1010 drivers/tty/serial/8250/8250_port.c:3401
console_emit_next_record kernel/printk/printk.c:2886 [inline]
console_flush_all+0x49c/0xcc0 kernel/printk/printk.c:2942
console_unlock+0xb8/0x1f0 kernel/printk/printk.c:3016
vprintk_emit+0x1bd/0x600 kernel/printk/printk.c:2316
vprintk+0x84/0xa0 kernel/printk/printk_safe.c:50
_printk+0xbf/0xf0 kernel/printk/printk.c:2337
register_console+0x7ef/0x10e0 kernel/printk/printk.c:3467
univ8250_console_init+0x38/0x50 drivers/tty/serial/8250/8250_core.c:688
console_init+0xba/0x5c0 kernel/printk/printk.c:3610
start_kernel+0x273/0x4d0 init/main.c:1081
secondary_startup_64_no_verify+0xce/0xdb
-> #1 (console_owner){....}-{0:0}:
console_lock_spinning_enable kernel/printk/printk.c:1867 [inline]
console_emit_next_record kernel/printk/printk.c:2880 [inline]
console_flush_all+0x472/0xcc0 kernel/printk/printk.c:2942
console_unlock+0xb8/0x1f0 kernel/printk/printk.c:3016
vprintk_emit+0x1bd/0x600 kernel/printk/printk.c:2316
vprintk+0x84/0xa0 kernel/printk/printk_safe.c:50
_printk+0xbf/0xf0 kernel/printk/printk.c:2337
build_zonelists+0x357/0x560 mm/page_alloc.c:6543
__build_all_zonelists+0x122/0x180 mm/page_alloc.c:6656
build_all_zonelists_init+0x1c/0x190 mm/page_alloc.c:6681
build_all_zonelists+0x4a/0x150 mm/page_alloc.c:6714
start_kernel+0xb7/0x4d0 init/main.c:975
secondary_startup_64_no_verify+0xce/0xdb
-> #0 (zonelist_update_seq.seqcount){...-}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3098 [inline]
check_prevs_add kernel/locking/lockdep.c:3217 [inline]
validate_chain kernel/locking/lockdep.c:3832 [inline]
__lock_acquire+0x2ec7/0x5d40 kernel/locking/lockdep.c:5056
lock_acquire kernel/locking/lockdep.c:5669 [inline]
lock_acquire+0x1af/0x520 kernel/locking/lockdep.c:5634
seqcount_lockdep_reader_access include/linux/seqlock.h:102 [inline]
read_seqbegin include/linux/seqlock.h:836 [inline]
zonelist_iter_begin mm/page_alloc.c:4765 [inline]
__alloc_pages_slowpath.constprop.0+0x15a/0x2170 mm/page_alloc.c:5086
__alloc_pages+0x408/0x4a0 mm/page_alloc.c:5605
__alloc_pages_node include/linux/gfp.h:237 [inline]
kmem_getpages mm/slab.c:1360 [inline]
cache_grow_begin+0x9b/0x3b0 mm/slab.c:2570
cache_alloc_refill+0x27f/0x380 mm/slab.c:2943
____cache_alloc mm/slab.c:3019 [inline]
____cache_alloc mm/slab.c:3002 [inline]
__do_cache_alloc mm/slab.c:3202 [inline]
slab_alloc_node mm/slab.c:3250 [inline]
__kmem_cache_alloc_node+0x360/0x3f0 mm/slab.c:3541
__do_kmalloc_node mm/slab_common.c:966 [inline]
__kmalloc+0x4e/0x190 mm/slab_common.c:980
kmalloc include/linux/slab.h:584 [inline]
tty_buffer_alloc+0x275/0x2f0 drivers/tty/tty_buffer.c:180
__tty_buffer_request_room+0x15b/0x2d0 drivers/tty/tty_buffer.c:278
tty_insert_flip_string_fixed_flag+0x90/0x250 drivers/tty/tty_buffer.c:327
tty_insert_flip_string include/linux/tty_flip.h:41 [inline]
tty_insert_flip_string_and_push_buffer+0x42/0x160 drivers/tty/tty_buffer.c:629
pty_write+0xda/0x100 drivers/tty/pty.c:118
ppp_async_push+0x5cb/0x1660 drivers/net/ppp/ppp_async.c:670
ppp_async_send+0xe2/0x110 drivers/net/ppp/ppp_async.c:638
__ppp_channel_push+0xe3/0x230 drivers/net/ppp/ppp_generic.c:2150
ppp_channel_push+0x1c2/0x250 drivers/net/ppp/ppp_generic.c:2177
ppp_write+0x22b/0x2d0 drivers/net/ppp/ppp_generic.c:523
do_loop_readv_writev fs/read_write.c:759 [inline]
do_loop_readv_writev fs/read_write.c:743 [inline]
do_iter_write+0x4ef/0x700 fs/read_write.c:863
vfs_writev+0x1aa/0x670 fs/read_write.c:934
do_pwritev fs/read_write.c:1031 [inline]
__do_sys_pwritev fs/read_write.c:1078 [inline]
__se_sys_pwritev fs/read_write.c:1073 [inline]
__x64_sys_pwritev+0x22f/0x310 fs/read_write.c:1073
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
other info that might help us debug this:
Chain exists of:
zonelist_update_seq.seqcount --> &port_lock_key --> &port->lock
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&port->lock);
lock(&port_lock_key);
lock(&port->lock);
lock(zonelist_update_seq.seqcount);
*** DEADLOCK ***
4 locks held by syz-executor930/5168:
#0: ffff888000630a48 (&pch->upl){.+..}-{2:2}, at: ppp_channel_push+0x28/0x250 drivers/net/ppp/ppp_generic.c:2171
#1: ffff8880006309e0 (&pch->downl){+...}-{2:2}, at: spin_lock include/linux/spinlock.h:350 [inline]
#1: ffff8880006309e0 (&pch->downl){+...}-{2:2}, at: __ppp_channel_push+0x2a/0x230 drivers/net/ppp/ppp_generic.c:2146
#2: ffff8880283b8030 (&ap->xmit_lock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:355 [inline]
#2: ffff8880283b8030 (&ap->xmit_lock){+...}-{2:2}, at: ppp_async_push+0xb2/0x1660 drivers/net/ppp/ppp_async.c:663
#3: ffff888014325958 (&port->lock){-...}-{2:2}, at: tty_insert_flip_string_and_push_buffer+0x2f/0x160 drivers/tty/tty_buffer.c:628
stack backtrace:
CPU: 0 PID: 5168 Comm: syz-executor930 Not tainted 6.3.0-rc3-syzkaller-00317-g65aca32efdcb #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106
check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2178
check_prev_add kernel/locking/lockdep.c:3098 [inline]
check_prevs_add kernel/locking/lockdep.c:3217 [inline]
validate_chain kernel/locking/lockdep.c:3832 [inline]
__lock_acquire+0x2ec7/0x5d40 kernel/locking/lockdep.c:5056
lock_acquire kernel/locking/lockdep.c:5669 [inline]
lock_acquire+0x1af/0x520 kernel/locking/lockdep.c:5634
seqcount_lockdep_reader_access include/linux/seqlock.h:102 [inline]
read_seqbegin include/linux/seqlock.h:836 [inline]
zonelist_iter_begin mm/page_alloc.c:4765 [inline]
__alloc_pages_slowpath.constprop.0+0x15a/0x2170 mm/page_alloc.c:5086
__alloc_pages+0x408/0x4a0 mm/page_alloc.c:5605
__alloc_pages_node include/linux/gfp.h:237 [inline]
kmem_getpages mm/slab.c:1360 [inline]
cache_grow_begin+0x9b/0x3b0 mm/slab.c:2570
cache_alloc_refill+0x27f/0x380 mm/slab.c:2943
____cache_alloc mm/slab.c:3019 [inline]
____cache_alloc mm/slab.c:3002 [inline]
__do_cache_alloc mm/slab.c:3202 [inline]
slab_alloc_node mm/slab.c:3250 [inline]
__kmem_cache_alloc_node+0x360/0x3f0 mm/slab.c:3541
__do_kmalloc_node mm/slab_common.c:966 [inline]
__kmalloc+0x4e/0x190 mm/slab_common.c:980
kmalloc include/linux/slab.h:584 [inline]
tty_buffer_alloc+0x275/0x2f0 drivers/tty/tty_buffer.c:180
__tty_buffer_request_room+0x15b/0x2d0 drivers/tty/tty_buffer.c:278
tty_insert_flip_string_fixed_flag+0x90/0x250 drivers/tty/tty_buffer.c:327
tty_insert_flip_string include/linux/tty_flip.h:41 [inline]
tty_insert_flip_string_and_push_buffer+0x42/0x160 drivers/tty/tty_buffer.c:629
pty_write+0xda/0x100 drivers/tty/pty.c:118
ppp_async_push+0x5cb/0x1660 drivers/net/ppp/ppp_async.c:670
ppp_async_send+0xe2/0x110 drivers/net/ppp/ppp_async.c:638
__ppp_channel_push+0xe3/0x230 drivers/net/ppp/ppp_generic.c:2150
ppp_channel_push+0x1c2/0x250 drivers/net/ppp/ppp_generic.c:2177
ppp_write+0x22b/0x2d0 drivers/net/ppp/ppp_generic.c:523
do_loop_readv_writev fs/read_write.c:759 [inline]
do_loop_readv_writev fs/read_write.c:743 [inline]
do_iter_write+0x4ef/0x700 fs/read_write.c:863
vfs_writev+0x1aa/0x670 fs/read_write.c:934
do_pwritev fs/read_write.c:1031 [inline]
__do_sys_pwritev fs/read_write.c:1078 [inline]
__se_sys_pwritev fs/read_write.c:1073 [inline]
__x64_sys_pwritev+0x22f/0x310 fs/read_write.c:1073
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: 0033:0x7f76be0b97d9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 41 15 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:00007fffcac24418 EFLAGS: 00000246 ORIG_RAX: 0000000000000128
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f76be0b97d9
RDX: 0000000000000003 RSI: 0000000020000380 RDI: 0000000000000004
RBP: 0000000000000000 R08: 0000000000000004 R09: 000000000000000d
R10: 00000000000000f1 R11: 0000000000000246 R12: 00007fffcac24430
R13: 00000000000f4240 R14: 0000000000000000 R15: 0000000000000000
</TASK>
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH] mm/page_alloc: don't check zonelist_update_seq from atomic allocations
2022-10-03 8:44 ` Ilpo Järvinen
@ 2023-04-02 10:48 ` Tetsuo Handa
0 siblings, 0 replies; 4+ messages in thread
From: Tetsuo Handa @ 2023-04-02 10:48 UTC (permalink / raw)
To: Mel Gorman, Patrick Daly, Michal Hocko, David Hildenbrand,
Andrew Morton
Cc: syzkaller-bugs, Ilpo Järvinen, syzbot, linux-mm
syzbot is reporting circular locking dependency which involves
zonelist_update_seq seqlock, for zonelist_update_seq is checked
while doing GFP_ATOMIC allocation.
Since zonelist_update_seq is checked for avoiding unnecessary OOM kill,
there is no need to check zonelist_update_seq for memory allocations
which will fail without OOM kill.
Therefore, let's keep locking dependency simple, by not checking
zonelist_update_seq from !__GFP_DIRECT_RECLAIM allocations.
Reported-by: syzbot <syzbot+223c7461c58c58a4cb10@syzkaller.appspotmail.com>
Link: https://syzkaller.appspot.com/bug?extid=223c7461c58c58a4cb10
Fixes: 3d36424b3b58 ("mm/page_alloc: fix race condition between build_all_zonelists and page allocation")
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
---
mm/page_alloc.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 7136c36c5d01..80ef79b23865 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -4759,17 +4759,17 @@ EXPORT_SYMBOL_GPL(fs_reclaim_release);
*/
static DEFINE_SEQLOCK(zonelist_update_seq);
-static unsigned int zonelist_iter_begin(void)
+static unsigned int zonelist_iter_begin(gfp_t gfp_mask)
{
- if (IS_ENABLED(CONFIG_MEMORY_HOTREMOVE))
+ if (IS_ENABLED(CONFIG_MEMORY_HOTREMOVE) && (gfp_mask & __GFP_DIRECT_RECLAIM))
return read_seqbegin(&zonelist_update_seq);
return 0;
}
-static unsigned int check_retry_zonelist(unsigned int seq)
+static unsigned int check_retry_zonelist(unsigned int seq, gfp_t gfp_mask)
{
- if (IS_ENABLED(CONFIG_MEMORY_HOTREMOVE))
+ if (IS_ENABLED(CONFIG_MEMORY_HOTREMOVE) && (gfp_mask & __GFP_DIRECT_RECLAIM))
return read_seqretry(&zonelist_update_seq, seq);
return seq;
@@ -5083,7 +5083,7 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
no_progress_loops = 0;
compact_priority = DEF_COMPACT_PRIORITY;
cpuset_mems_cookie = read_mems_allowed_begin();
- zonelist_iter_cookie = zonelist_iter_begin();
+ zonelist_iter_cookie = zonelist_iter_begin(gfp_mask);
/*
* The fast path uses conservative alloc_flags to succeed only until
@@ -5261,7 +5261,7 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
* a unnecessary OOM kill.
*/
if (check_retry_cpuset(cpuset_mems_cookie, ac) ||
- check_retry_zonelist(zonelist_iter_cookie))
+ check_retry_zonelist(zonelist_iter_cookie, gfp_mask))
goto restart;
/* Reclaim has failed us, start killing things */
@@ -5287,7 +5287,7 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
* a unnecessary OOM kill.
*/
if (check_retry_cpuset(cpuset_mems_cookie, ac) ||
- check_retry_zonelist(zonelist_iter_cookie))
+ check_retry_zonelist(zonelist_iter_cookie, gfp_mask))
goto restart;
/*
--
2.34.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
end of thread, other threads:[~2023-04-02 10:48 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
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2022-09-30 22:05 [syzbot] possible deadlock in tty_port_tty_get syzbot
2022-10-03 8:44 ` Ilpo Järvinen
2023-04-02 10:48 ` [PATCH] mm/page_alloc: don't check zonelist_update_seq from atomic allocations Tetsuo Handa
2023-03-25 23:02 ` [syzbot] [serial?] possible deadlock in tty_port_tty_get syzbot
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