From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org,
syzbot+22e87cdf94021b984aa6@syzkaller.appspotmail.com,
syzbot+c5e32344981ad9f33750@syzkaller.appspotmail.com,
Boqun Feng <boqun.feng@gmail.com>,
Jeff Layton <jlayton@kernel.org>
Subject: [PATCH 5.4 33/47] fcntl: Fix potential deadlock in send_sig{io, urg}()
Date: Mon, 4 Jan 2021 16:57:32 +0100 [thread overview]
Message-ID: <20210104155707.335126873@linuxfoundation.org> (raw)
In-Reply-To: <20210104155705.740576914@linuxfoundation.org>
From: Boqun Feng <boqun.feng@gmail.com>
commit 8d1ddb5e79374fb277985a6b3faa2ed8631c5b4c upstream.
Syzbot reports a potential deadlock found by the newly added recursive
read deadlock detection in lockdep:
[...] ========================================================
[...] WARNING: possible irq lock inversion dependency detected
[...] 5.9.0-rc2-syzkaller #0 Not tainted
[...] --------------------------------------------------------
[...] syz-executor.1/10214 just changed the state of lock:
[...] ffff88811f506338 (&f->f_owner.lock){.+..}-{2:2}, at: send_sigurg+0x1d/0x200
[...] but this lock was taken by another, HARDIRQ-safe lock in the past:
[...] (&dev->event_lock){-...}-{2:2}
[...]
[...]
[...] and interrupts could create inverse lock ordering between them.
[...]
[...]
[...] other info that might help us debug this:
[...] Chain exists of:
[...] &dev->event_lock --> &new->fa_lock --> &f->f_owner.lock
[...]
[...] Possible interrupt unsafe locking scenario:
[...]
[...] CPU0 CPU1
[...] ---- ----
[...] lock(&f->f_owner.lock);
[...] local_irq_disable();
[...] lock(&dev->event_lock);
[...] lock(&new->fa_lock);
[...] <Interrupt>
[...] lock(&dev->event_lock);
[...]
[...] *** DEADLOCK ***
The corresponding deadlock case is as followed:
CPU 0 CPU 1 CPU 2
read_lock(&fown->lock);
spin_lock_irqsave(&dev->event_lock, ...)
write_lock_irq(&filp->f_owner.lock); // wait for the lock
read_lock(&fown-lock); // have to wait until the writer release
// due to the fairness
<interrupted>
spin_lock_irqsave(&dev->event_lock); // wait for the lock
The lock dependency on CPU 1 happens if there exists a call sequence:
input_inject_event():
spin_lock_irqsave(&dev->event_lock,...);
input_handle_event():
input_pass_values():
input_to_handler():
handler->event(): // evdev_event()
evdev_pass_values():
spin_lock(&client->buffer_lock);
__pass_event():
kill_fasync():
kill_fasync_rcu():
read_lock(&fa->fa_lock);
send_sigio():
read_lock(&fown->lock);
To fix this, make the reader in send_sigurg() and send_sigio() use
read_lock_irqsave() and read_lock_irqrestore().
Reported-by: syzbot+22e87cdf94021b984aa6@syzkaller.appspotmail.com
Reported-by: syzbot+c5e32344981ad9f33750@syzkaller.appspotmail.com
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/fcntl.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
--- a/fs/fcntl.c
+++ b/fs/fcntl.c
@@ -779,9 +779,10 @@ void send_sigio(struct fown_struct *fown
{
struct task_struct *p;
enum pid_type type;
+ unsigned long flags;
struct pid *pid;
- read_lock(&fown->lock);
+ read_lock_irqsave(&fown->lock, flags);
type = fown->pid_type;
pid = fown->pid;
@@ -802,7 +803,7 @@ void send_sigio(struct fown_struct *fown
read_unlock(&tasklist_lock);
}
out_unlock_fown:
- read_unlock(&fown->lock);
+ read_unlock_irqrestore(&fown->lock, flags);
}
static void send_sigurg_to_task(struct task_struct *p,
@@ -817,9 +818,10 @@ int send_sigurg(struct fown_struct *fown
struct task_struct *p;
enum pid_type type;
struct pid *pid;
+ unsigned long flags;
int ret = 0;
- read_lock(&fown->lock);
+ read_lock_irqsave(&fown->lock, flags);
type = fown->pid_type;
pid = fown->pid;
@@ -842,7 +844,7 @@ int send_sigurg(struct fown_struct *fown
read_unlock(&tasklist_lock);
}
out_unlock_fown:
- read_unlock(&fown->lock);
+ read_unlock_irqrestore(&fown->lock, flags);
return ret;
}
next prev parent reply other threads:[~2021-01-04 16:00 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-04 15:56 [PATCH 5.4 00/47] 5.4.87-rc1 review Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 5.4 01/47] net/sched: sch_taprio: reset child qdiscs before freeing them Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 5.4 02/47] md/raid10: initialize r10_bio->read_slot before use Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 5.4 03/47] thermal/drivers/cpufreq_cooling: Update cpufreq_state only if state has changed Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 5.4 04/47] ext4: prevent creating duplicate encrypted filenames Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 5.4 05/47] ubifs: " Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 5.4 06/47] f2fs: " Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 5.4 07/47] fscrypt: add fscrypt_is_nokey_name() Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 5.4 08/47] fscrypt: remove kernel-internal constants from UAPI header Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 5.4 09/47] vfio/pci: Move dummy_resources_list init in vfio_pci_probe() Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 5.4 10/47] btrfs: fix race when defragmenting leads to unnecessary IO Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 5.4 11/47] ext4: dont remount read-only with errors=continue on reboot Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 5.4 12/47] KVM: x86: avoid incorrect writes to host MSR_IA32_SPEC_CTRL Greg Kroah-Hartman
2021-02-26 11:03 ` Thomas Lamprecht
2021-02-26 11:27 ` Paolo Bonzini
2021-02-26 12:59 ` Greg Kroah-Hartman
2021-02-26 14:15 ` Paolo Bonzini
2021-02-26 14:18 ` Thomas Lamprecht
2021-02-26 14:21 ` Paolo Bonzini
2021-01-04 15:57 ` [PATCH 5.4 13/47] KVM: SVM: relax conditions for allowing MSR_IA32_SPEC_CTRL accesses Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 5.4 14/47] KVM: x86: reinstate vendor-agnostic check on SPEC_CTRL cpuid bits Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 5.4 15/47] powerpc/bitops: Fix possible undefined behaviour with fls() and fls64() Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 5.4 16/47] jffs2: Allow setting rp_size to zero during remounting Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 5.4 17/47] jffs2: Fix NULL pointer dereference in rp_size fs option parsing Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 5.4 18/47] scsi: block: Fix a race in the runtime power management code Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 5.4 19/47] uapi: move constants from <linux/kernel.h> to <linux/const.h> Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 5.4 20/47] tools headers UAPI: Sync linux/const.h with the kernel headers Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 5.4 21/47] null_blk: Fix zone size initialization Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 5.4 22/47] of: fix linker-section match-table corruption Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 5.4 23/47] cgroup: Fix memory leak when parsing multiple source parameters Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 5.4 24/47] scsi: cxgb4i: Fix TLS dependency Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 5.4 25/47] Bluetooth: hci_h5: close serdev device and free hu in h5_close Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 5.4 26/47] reiserfs: add check for an invalid ih_entry_count Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 5.4 27/47] misc: vmw_vmci: fix kernel info-leak by initializing dbells in vmci_ctx_get_chkpt_doorbells() Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 5.4 28/47] media: gp8psk: initialize stats at power control logic Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 5.4 29/47] f2fs: fix shift-out-of-bounds in sanity_check_raw_super() Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 5.4 30/47] ALSA: seq: Use bool for snd_seq_queue internal flags Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 5.4 31/47] ALSA: rawmidi: Access runtime->avail always in spinlock Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 5.4 32/47] bfs: dont use WARNING: string when its just info Greg Kroah-Hartman
2021-01-04 15:57 ` Greg Kroah-Hartman [this message]
2021-01-04 15:57 ` [PATCH 5.4 34/47] rtc: sun6i: Fix memleak in sun6i_rtc_clk_init Greg Kroah-Hartman
2021-01-06 13:07 ` Pavel Machek
2021-01-04 15:57 ` [PATCH 5.4 35/47] module: set MODULE_STATE_GOING state when a module fails to load Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 5.4 36/47] quota: Dont overflow quota file offsets Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 5.4 37/47] rtc: pl031: fix resource leak in pl031_probe Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 5.4 38/47] powerpc: sysdev: add missing iounmap() on error in mpic_msgr_probe() Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 5.4 39/47] i3c master: fix missing destroy_workqueue() on error in i3c_master_register Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 5.4 40/47] NFSv4: Fix a pNFS layout related use-after-free race when freeing the inode Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 5.4 41/47] f2fs: avoid race condition for shrinker count Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 5.4 42/47] module: delay kobject uevent until after module init call Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 5.4 43/47] fs/namespace.c: WARN if mnt_count has become negative Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 5.4 44/47] um: ubd: Submit all data segments atomically Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 5.4 45/47] tick/sched: Remove bogus boot "safety" check Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 5.4 46/47] ALSA: pcm: Clear the full allocated memory at hw_params Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 5.4 47/47] dm verity: skip verity work if I/O error when system is shutting down Greg Kroah-Hartman
2021-01-05 6:07 ` [PATCH 5.4 00/47] 5.4.87-rc1 review Daniel Díaz
2021-01-05 16:39 ` Shuah Khan
2021-01-05 18:17 ` Guenter Roeck
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210104155707.335126873@linuxfoundation.org \
--to=gregkh@linuxfoundation.org \
--cc=boqun.feng@gmail.com \
--cc=jlayton@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=stable@vger.kernel.org \
--cc=syzbot+22e87cdf94021b984aa6@syzkaller.appspotmail.com \
--cc=syzbot+c5e32344981ad9f33750@syzkaller.appspotmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).