* [syzbot] [crypto?] INFO: task hung in hwrng_fillfn
@ 2023-11-25 13:21 syzbot
2023-11-26 3:52 ` syzbot
` (5 more replies)
0 siblings, 6 replies; 14+ messages in thread
From: syzbot @ 2023-11-25 13:21 UTC (permalink / raw)
To: davem, herbert, linux-crypto, linux-kernel, olivia, syzkaller-bugs
Hello,
syzbot found the following issue on:
HEAD commit: 98b1cc82c4af Linux 6.7-rc2
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12e89e10e80000
kernel config: https://syzkaller.appspot.com/x/.config?x=6ae1a4ee971a7305
dashboard link: https://syzkaller.appspot.com/bug?extid=c52ab18308964d248092
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=174f0bd4e80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14b83b84e80000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/39c6cdad13fc/disk-98b1cc82.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/5a77b5daef9b/vmlinux-98b1cc82.xz
kernel image: https://storage.googleapis.com/syzbot-assets/5e09ae712e0d/bzImage-98b1cc82.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c52ab18308964d248092@syzkaller.appspotmail.com
INFO: task hwrng:749 blocked for more than 143 seconds.
Not tainted 6.7.0-rc2-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:hwrng state:D stack:29040 pid:749 tgid:749 ppid:2 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5376 [inline]
__schedule+0xedb/0x5af0 kernel/sched/core.c:6688
__schedule_loop kernel/sched/core.c:6763 [inline]
schedule+0xe9/0x270 kernel/sched/core.c:6778
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6835
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x5b9/0x9d0 kernel/locking/mutex.c:747
hwrng_fillfn+0x145/0x430 drivers/char/hw_random/core.c:504
kthread+0x2c6/0x3a0 kernel/kthread.c:388
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242
</TASK>
Showing all locks held in the system:
1 lock held by khungtaskd/29:
#0: ffffffff8cfabce0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:301 [inline]
#0: ffffffff8cfabce0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:747 [inline]
#0: ffffffff8cfabce0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x75/0x340 kernel/locking/lockdep.c:6613
2 locks held by kswapd0/86:
1 lock held by hwrng/749:
#0: ffffffff8dbafee8 (reading_mutex){+.+.}-{3:3}, at: hwrng_fillfn+0x145/0x430 drivers/char/hw_random/core.c:504
2 locks held by getty/4824:
#0: ffff888025fa10a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc90002f062f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xfc6/0x1490 drivers/tty/n_tty.c:2201
2 locks held by syz-executor391/5105:
2 locks held by syz-executor391/5106:
=============================================
NMI backtrace for cpu 1
CPU: 1 PID: 29 Comm: khungtaskd Not tainted 6.7.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
nmi_cpu_backtrace+0x277/0x390 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x299/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline]
watchdog+0xf87/0x1210 kernel/hung_task.c:379
kthread+0x2c6/0x3a0 kernel/kthread.c:388
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242
</TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 5105 Comm: syz-executor391 Not tainted 6.7.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023
RIP: 0010:__lock_acquire+0x30/0x3b10 kernel/locking/lockdep.c:4992
Code: f6 41 55 41 54 49 89 fc 55 89 d5 53 44 89 cb 48 81 ec f0 00 00 00 48 8b 84 24 28 01 00 00 48 c7 84 24 90 00 00 00 b3 8a b5 41 <44> 89 44 24 08 44 8b ac 24 48 01 00 00 48 c7 84 24 98 00 00 00 1b
RSP: 0018:ffffc900044271d8 EFLAGS: 00000086
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000002
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8cfabce0
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffff8f1934d7 R11: 0000000000000002 R12: ffffffff8cfabce0
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS: 00007f3c785f96c0(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005565d7bb9be7 CR3: 000000001af30000 CR4: 0000000000350ef0
Call Trace:
<NMI>
</NMI>
<TASK>
lock_acquire kernel/locking/lockdep.c:5753 [inline]
lock_acquire+0x1ae/0x520 kernel/locking/lockdep.c:5718
rcu_lock_acquire include/linux/rcupdate.h:301 [inline]
rcu_read_lock include/linux/rcupdate.h:747 [inline]
get_mem_cgroup_from_mm+0x4b/0x4c0 mm/memcontrol.c:1081
__mem_cgroup_charge+0x1c/0x140 mm/memcontrol.c:7224
mem_cgroup_charge include/linux/memcontrol.h:684 [inline]
__filemap_add_folio+0x88c/0xed0 mm/filemap.c:854
filemap_add_folio+0xb1/0x1e0 mm/filemap.c:937
page_cache_ra_unbounded+0x1d0/0x5f0 mm/readahead.c:250
do_page_cache_ra mm/readahead.c:299 [inline]
page_cache_ra_order+0x72b/0xa80 mm/readahead.c:546
do_sync_mmap_readahead mm/filemap.c:3141 [inline]
filemap_fault+0x16a8/0x3570 mm/filemap.c:3233
__do_fault+0x107/0x600 mm/memory.c:4265
do_cow_fault mm/memory.c:4662 [inline]
do_fault mm/memory.c:4764 [inline]
do_pte_missing mm/memory.c:3730 [inline]
handle_pte_fault mm/memory.c:5038 [inline]
__handle_mm_fault+0x3a8d/0x3d70 mm/memory.c:5179
handle_mm_fault+0x47a/0xa10 mm/memory.c:5344
do_user_addr_fault+0x3d1/0x1000 arch/x86/mm/fault.c:1413
handle_page_fault arch/x86/mm/fault.c:1505 [inline]
exc_page_fault+0x5d/0xc0 arch/x86/mm/fault.c:1561
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:570
RIP: 0010:rep_movs_alternative+0x57/0x70 arch/x86/lib/copy_user_64.S:80
Code: 00 66 90 48 8b 06 48 89 07 48 83 c6 08 48 83 c7 08 83 e9 08 74 df 83 f9 08 73 e8 eb c9 eb 01 c3 48 89 c8 48 c1 e9 03 83 e0 07 <f3> 48 a5 89 c1 85 c9 75 b3 c3 48 8d 0c c8 eb ac 66 0f 1f 84 00 00
RSP: 0018:ffffc90004427bb0 EFLAGS: 00050246
RAX: 0000000000000000 RBX: 0000000000000040 RCX: 0000000000000008
RDX: ffffed1028a4ab48 RSI: ffff888145255a00 RDI: 0000000020019980
RBP: 0000000020019980 R08: 0000000000000000 R09: ffffed1028a4ab47
R10: ffff888145255a3f R11: 0000000000000001 R12: ffff888145255a00
R13: 00000000200199c0 R14: 0000000000000000 R15: dffffc0000000000
copy_user_generic arch/x86/include/asm/uaccess_64.h:112 [inline]
raw_copy_to_user arch/x86/include/asm/uaccess_64.h:133 [inline]
_copy_to_user lib/usercopy.c:41 [inline]
_copy_to_user+0xa8/0xb0 lib/usercopy.c:34
copy_to_user include/linux/uaccess.h:191 [inline]
rng_dev_read+0x184/0x580 drivers/char/hw_random/core.c:255
do_loop_readv_writev fs/read_write.c:755 [inline]
do_loop_readv_writev fs/read_write.c:743 [inline]
do_iter_read+0x567/0x830 fs/read_write.c:797
vfs_readv+0x12d/0x1a0 fs/read_write.c:915
do_preadv fs/read_write.c:1007 [inline]
__do_sys_preadv fs/read_write.c:1057 [inline]
__se_sys_preadv fs/read_write.c:1052 [inline]
__x64_sys_preadv+0x228/0x300 fs/read_write.c:1052
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x40/0x110 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x63/0x6b
RIP: 0033:0x7f3c78638b29
Code: Unable to access opcode bytes at 0x7f3c78638aff.
RSP: 002b:00007f3c785f9168 EFLAGS: 00000246 ORIG_RAX: 0000000000000127
RAX: ffffffffffffffda RBX: 00007f3c786c2328 RCX: 00007f3c78638b29
RDX: 0000000000000001 RSI: 0000000020001880 RDI: 0000000000000003
RBP: 00007f3c786c2320 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f3c786c232c
R13: 0000000000000000 R14: 00007ffc8a220310 R15: 00007ffc8a2203f8
</TASK>
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.464 msecs
---
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.
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [syzbot] [crypto?] INFO: task hung in hwrng_fillfn
2023-11-25 13:21 [syzbot] [crypto?] INFO: task hung in hwrng_fillfn syzbot
@ 2023-11-26 3:52 ` syzbot
2023-11-26 4:05 ` syzbot
` (4 subsequent siblings)
5 siblings, 0 replies; 14+ messages in thread
From: syzbot @ 2023-11-26 3:52 UTC (permalink / raw)
To: linux-kernel
For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org.
***
Subject: [crypto?] INFO: task hung in hwrng_fillfn
Author: eadavis@qq.com
please test task hung in hwrng_fillfn
#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 98b1cc82c4af
diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
index 420f155d251f..ebfa5eab84df 100644
--- a/drivers/char/hw_random/core.c
+++ b/drivers/char/hw_random/core.c
@@ -501,7 +501,10 @@ static int hwrng_fillfn(void *unused)
rng = get_current_rng();
if (IS_ERR(rng) || !rng)
break;
- mutex_lock(&reading_mutex);
+ if (mutex_lock_interruptible(&reading_mutex)) {
+ put_rng(rng);
+ return = -ERESTARTSYS;
+ }
rc = rng_get_data(rng, rng_fillbuf,
rng_buffer_size(), 1);
if (current_quality != rng->quality)
^ permalink raw reply related [flat|nested] 14+ messages in thread
* Re: [syzbot] [crypto?] INFO: task hung in hwrng_fillfn
2023-11-25 13:21 [syzbot] [crypto?] INFO: task hung in hwrng_fillfn syzbot
2023-11-26 3:52 ` syzbot
@ 2023-11-26 4:05 ` syzbot
2023-11-26 4:06 ` syzbot
` (3 subsequent siblings)
5 siblings, 0 replies; 14+ messages in thread
From: syzbot @ 2023-11-26 4:05 UTC (permalink / raw)
To: linux-kernel
For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org.
***
Subject: [crypto?] INFO: task hung in hwrng_fillfn
Author: eadavis@qq.com
please test task hung in hwrng_fillfn
#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 98b1cc82c4af
diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
index 420f155d251f..883412bbf9f2 100644
--- a/drivers/char/hw_random/core.c
+++ b/drivers/char/hw_random/core.c
@@ -225,17 +225,18 @@ static ssize_t rng_dev_read(struct file *filp, char __user *buf,
goto out;
}
- if (mutex_lock_interruptible(&reading_mutex)) {
- err = -ERESTARTSYS;
- goto out_put;
- }
if (!data_avail) {
+ if (mutex_lock_interruptible(&reading_mutex)) {
+ err = -ERESTARTSYS;
+ goto out_put;
+ }
bytes_read = rng_get_data(rng, rng_buffer,
rng_buffer_size(),
!(filp->f_flags & O_NONBLOCK));
+ mutex_unlock(&reading_mutex);
if (bytes_read < 0) {
err = bytes_read;
- goto out_unlock_reading;
+ goto out_put;
}
data_avail = bytes_read;
}
@@ -243,7 +244,7 @@ static ssize_t rng_dev_read(struct file *filp, char __user *buf,
if (!data_avail) {
if (filp->f_flags & O_NONBLOCK) {
err = -EAGAIN;
- goto out_unlock_reading;
+ goto out_put;
}
} else {
len = data_avail;
@@ -255,14 +256,13 @@ static ssize_t rng_dev_read(struct file *filp, char __user *buf,
if (copy_to_user(buf + ret, rng_buffer + data_avail,
len)) {
err = -EFAULT;
- goto out_unlock_reading;
+ goto out_put;
}
size -= len;
ret += len;
}
- mutex_unlock(&reading_mutex);
put_rng(rng);
if (need_resched())
@@ -276,8 +276,6 @@ static ssize_t rng_dev_read(struct file *filp, char __user *buf,
out:
return ret ? : err;
-out_unlock_reading:
- mutex_unlock(&reading_mutex);
out_put:
put_rng(rng);
goto out;
@@ -501,7 +499,10 @@ static int hwrng_fillfn(void *unused)
rng = get_current_rng();
if (IS_ERR(rng) || !rng)
break;
- mutex_lock(&reading_mutex);
+ if (mutex_lock_interruptible(&reading_mutex)) {
+ put_rng(rng);
+ return = -ERESTARTSYS;
+ }
rc = rng_get_data(rng, rng_fillbuf,
rng_buffer_size(), 1);
if (current_quality != rng->quality)
^ permalink raw reply related [flat|nested] 14+ messages in thread
* Re: [syzbot] [crypto?] INFO: task hung in hwrng_fillfn
2023-11-25 13:21 [syzbot] [crypto?] INFO: task hung in hwrng_fillfn syzbot
2023-11-26 3:52 ` syzbot
2023-11-26 4:05 ` syzbot
@ 2023-11-26 4:06 ` syzbot
2023-11-26 5:35 ` syzbot
` (2 subsequent siblings)
5 siblings, 0 replies; 14+ messages in thread
From: syzbot @ 2023-11-26 4:06 UTC (permalink / raw)
To: linux-kernel
For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org.
***
Subject: [crypto?] INFO: task hung in hwrng_fillfn
Author: eadavis@qq.com
please test task hung in hwrng_fillfn
#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 98b1cc82c4af
diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
index 420f155d251f..883412bbf9f2 100644
--- a/drivers/char/hw_random/core.c
+++ b/drivers/char/hw_random/core.c
@@ -225,17 +225,18 @@ static ssize_t rng_dev_read(struct file *filp, char __user *buf,
goto out;
}
- if (mutex_lock_interruptible(&reading_mutex)) {
- err = -ERESTARTSYS;
- goto out_put;
- }
if (!data_avail) {
+ if (mutex_lock_interruptible(&reading_mutex)) {
+ err = -ERESTARTSYS;
+ goto out_put;
+ }
bytes_read = rng_get_data(rng, rng_buffer,
rng_buffer_size(),
!(filp->f_flags & O_NONBLOCK));
+ mutex_unlock(&reading_mutex);
if (bytes_read < 0) {
err = bytes_read;
- goto out_unlock_reading;
+ goto out_put;
}
data_avail = bytes_read;
}
@@ -243,7 +244,7 @@ static ssize_t rng_dev_read(struct file *filp, char __user *buf,
if (!data_avail) {
if (filp->f_flags & O_NONBLOCK) {
err = -EAGAIN;
- goto out_unlock_reading;
+ goto out_put;
}
} else {
len = data_avail;
@@ -255,14 +256,13 @@ static ssize_t rng_dev_read(struct file *filp, char __user *buf,
if (copy_to_user(buf + ret, rng_buffer + data_avail,
len)) {
err = -EFAULT;
- goto out_unlock_reading;
+ goto out_put;
}
size -= len;
ret += len;
}
- mutex_unlock(&reading_mutex);
put_rng(rng);
if (need_resched())
@@ -276,8 +276,6 @@ static ssize_t rng_dev_read(struct file *filp, char __user *buf,
out:
return ret ? : err;
-out_unlock_reading:
- mutex_unlock(&reading_mutex);
out_put:
put_rng(rng);
goto out;
@@ -501,7 +499,10 @@ static int hwrng_fillfn(void *unused)
rng = get_current_rng();
if (IS_ERR(rng) || !rng)
break;
- mutex_lock(&reading_mutex);
+ if (mutex_lock_interruptible(&reading_mutex)) {
+ put_rng(rng);
+ return -ERESTARTSYS;
+ }
rc = rng_get_data(rng, rng_fillbuf,
rng_buffer_size(), 1);
if (current_quality != rng->quality)
^ permalink raw reply related [flat|nested] 14+ messages in thread
* Re: [syzbot] [crypto?] INFO: task hung in hwrng_fillfn
2023-11-25 13:21 [syzbot] [crypto?] INFO: task hung in hwrng_fillfn syzbot
` (2 preceding siblings ...)
2023-11-26 4:06 ` syzbot
@ 2023-11-26 5:35 ` syzbot
2023-11-26 7:07 ` [PATCH] hwrng: core - fix " Edward Adam Davis
2023-11-29 2:59 ` [syzbot] [wireless?] WARNING in rate_control_rate_init syzbot
5 siblings, 0 replies; 14+ messages in thread
From: syzbot @ 2023-11-26 5:35 UTC (permalink / raw)
To: linux-kernel
For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org.
***
Subject: [crypto?] INFO: task hung in hwrng_fillfn
Author: eadavis@qq.com
please test task hung in hwrng_fillfn
#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 98b1cc82c4af
diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
index 420f155d251f..883412bbf9f2 100644
--- a/drivers/char/hw_random/core.c
+++ b/drivers/char/hw_random/core.c
@@ -225,17 +225,18 @@ static ssize_t rng_dev_read(struct file *filp, char __user *buf,
goto out;
}
- if (mutex_lock_interruptible(&reading_mutex)) {
- err = -ERESTARTSYS;
- goto out_put;
- }
if (!data_avail) {
+ if (mutex_lock_interruptible(&reading_mutex)) {
+ err = -ERESTARTSYS;
+ goto out_put;
+ }
bytes_read = rng_get_data(rng, rng_buffer,
rng_buffer_size(),
!(filp->f_flags & O_NONBLOCK));
+ mutex_unlock(&reading_mutex);
if (bytes_read < 0) {
err = bytes_read;
- goto out_unlock_reading;
+ goto out_put;
}
data_avail = bytes_read;
}
@@ -243,7 +244,7 @@ static ssize_t rng_dev_read(struct file *filp, char __user *buf,
if (!data_avail) {
if (filp->f_flags & O_NONBLOCK) {
err = -EAGAIN;
- goto out_unlock_reading;
+ goto out_put;
}
} else {
len = data_avail;
@@ -255,14 +256,13 @@ static ssize_t rng_dev_read(struct file *filp, char __user *buf,
if (copy_to_user(buf + ret, rng_buffer + data_avail,
len)) {
err = -EFAULT;
- goto out_unlock_reading;
+ goto out_put;
}
size -= len;
ret += len;
}
- mutex_unlock(&reading_mutex);
put_rng(rng);
if (need_resched())
@@ -276,8 +276,6 @@ static ssize_t rng_dev_read(struct file *filp, char __user *buf,
out:
return ret ? : err;
-out_unlock_reading:
- mutex_unlock(&reading_mutex);
out_put:
put_rng(rng);
goto out;
@@ -501,7 +499,10 @@ static int hwrng_fillfn(void *unused)
rng = get_current_rng();
if (IS_ERR(rng) || !rng)
break;
- mutex_lock(&reading_mutex);
+ if (mutex_lock_interruptible(&reading_mutex)) {
+ put_rng(rng);
+ return -ERESTARTSYS;
+ }
rc = rng_get_data(rng, rng_fillbuf,
rng_buffer_size(), 1);
if (current_quality != rng->quality)
^ permalink raw reply related [flat|nested] 14+ messages in thread
* [PATCH] hwrng: core - fix task hung in hwrng_fillfn
2023-11-25 13:21 [syzbot] [crypto?] INFO: task hung in hwrng_fillfn syzbot
` (3 preceding siblings ...)
2023-11-26 5:35 ` syzbot
@ 2023-11-26 7:07 ` Edward Adam Davis
2023-12-01 9:56 ` Herbert Xu
2023-11-29 2:59 ` [syzbot] [wireless?] WARNING in rate_control_rate_init syzbot
5 siblings, 1 reply; 14+ messages in thread
From: Edward Adam Davis @ 2023-11-26 7:07 UTC (permalink / raw)
To: syzbot+c52ab18308964d248092
Cc: davem, herbert, linux-crypto, linux-kernel, olivia, syzkaller-bugs
[Syz repo]
INFO: task hwrng:749 blocked for more than 143 seconds.
Not tainted 6.7.0-rc2-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:hwrng state:D stack:29040 pid:749 tgid:749 ppid:2 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5376 [inline]
__schedule+0xedb/0x5af0 kernel/sched/core.c:6688
__schedule_loop kernel/sched/core.c:6763 [inline]
schedule+0xe9/0x270 kernel/sched/core.c:6778
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6835
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x5b9/0x9d0 kernel/locking/mutex.c:747
hwrng_fillfn+0x145/0x430 drivers/char/hw_random/core.c:504
kthread+0x2c6/0x3a0 kernel/kthread.c:388
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242
</TASK>
...
RIP: 0010:rep_movs_alternative+0x57/0x70 arch/x86/lib/copy_user_64.S:80
Code: 00 66 90 48 8b 06 48 89 07 48 83 c6 08 48 83 c7 08 83 e9 08 74 df 83 f9 08 73 e8 eb c9 eb 01 c3 48 89 c8 48 c1 e9 03 83 e0 07 <f3> 48 a5 89 c1 85 c9 75 b3 c3 48 8d 0c c8 eb ac 66 0f 1f 84 00 00
RSP: 0018:ffffc90004427bb0 EFLAGS: 00050246
RAX: 0000000000000000 RBX: 0000000000000040 RCX: 0000000000000008
RDX: ffffed1028a4ab48 RSI: ffff888145255a00 RDI: 0000000020019980
RBP: 0000000020019980 R08: 0000000000000000 R09: ffffed1028a4ab47
R10: ffff888145255a3f R11: 0000000000000001 R12: ffff888145255a00
R13: 00000000200199c0 R14: 0000000000000000 R15: dffffc0000000000
copy_user_generic arch/x86/include/asm/uaccess_64.h:112 [inline]
raw_copy_to_user arch/x86/include/asm/uaccess_64.h:133 [inline]
_copy_to_user lib/usercopy.c:41 [inline]
_copy_to_user+0xa8/0xb0 lib/usercopy.c:34
copy_to_user include/linux/uaccess.h:191 [inline]
rng_dev_read+0x184/0x580 drivers/char/hw_random/core.c:255
do_loop_readv_writev fs/read_write.c:755 [inline]
do_loop_readv_writev fs/read_write.c:743 [inline]
do_iter_read+0x567/0x830 fs/read_write.c:797
vfs_readv+0x12d/0x1a0 fs/read_write.c:915
do_preadv fs/read_write.c:1007 [inline]
__do_sys_preadv fs/read_write.c:1057 [inline]
__se_sys_preadv fs/read_write.c:1052 [inline]
__x64_sys_preadv+0x228/0x300 fs/read_write.c:1052
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x40/0x110 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x63/0x6b
[Analysis]
The lock reading_mutex in rng_dev_read() has been occupied for too long,
causing the thread callback function hwrng_fillfn() to wait for a timeout.
[Fix]
Move code that does not require this lock protection out of the critical area.
Reported-and-tested-by: syzbot+c52ab18308964d248092@syzkaller.appspotmail.com
Signed-off-by: Edward Adam Davis <eadavis@qq.com>
---
drivers/char/hw_random/core.c | 23 ++++++++++++-----------
1 file changed, 12 insertions(+), 11 deletions(-)
diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
index 420f155d251f..7323ddc958ce 100644
--- a/drivers/char/hw_random/core.c
+++ b/drivers/char/hw_random/core.c
@@ -225,17 +225,18 @@ static ssize_t rng_dev_read(struct file *filp, char __user *buf,
goto out;
}
- if (mutex_lock_interruptible(&reading_mutex)) {
- err = -ERESTARTSYS;
- goto out_put;
- }
if (!data_avail) {
+ if (mutex_lock_interruptible(&reading_mutex)) {
+ err = -ERESTARTSYS;
+ goto out_put;
+ }
bytes_read = rng_get_data(rng, rng_buffer,
rng_buffer_size(),
!(filp->f_flags & O_NONBLOCK));
+ mutex_unlock(&reading_mutex);
if (bytes_read < 0) {
err = bytes_read;
- goto out_unlock_reading;
+ goto out_put;
}
data_avail = bytes_read;
}
@@ -243,7 +244,7 @@ static ssize_t rng_dev_read(struct file *filp, char __user *buf,
if (!data_avail) {
if (filp->f_flags & O_NONBLOCK) {
err = -EAGAIN;
- goto out_unlock_reading;
+ goto out_put;
}
} else {
len = data_avail;
@@ -255,14 +256,13 @@ static ssize_t rng_dev_read(struct file *filp, char __user *buf,
if (copy_to_user(buf + ret, rng_buffer + data_avail,
len)) {
err = -EFAULT;
- goto out_unlock_reading;
+ goto out_put;
}
size -= len;
ret += len;
}
- mutex_unlock(&reading_mutex);
put_rng(rng);
if (need_resched())
@@ -276,8 +276,6 @@ static ssize_t rng_dev_read(struct file *filp, char __user *buf,
out:
return ret ? : err;
-out_unlock_reading:
- mutex_unlock(&reading_mutex);
out_put:
put_rng(rng);
goto out;
@@ -501,7 +499,10 @@ static int hwrng_fillfn(void *unused)
rng = get_current_rng();
if (IS_ERR(rng) || !rng)
break;
- mutex_lock(&reading_mutex);
+ if (mutex_lock_interruptible(&reading_mutex)) {
+ put_rng(rng);
+ return -ERESTARTSYS;
+ }
rc = rng_get_data(rng, rng_fillbuf,
rng_buffer_size(), 1);
if (current_quality != rng->quality)
--
2.25.1
^ permalink raw reply related [flat|nested] 14+ messages in thread
* Re: [syzbot] [wireless?] WARNING in rate_control_rate_init
2023-11-25 13:21 [syzbot] [crypto?] INFO: task hung in hwrng_fillfn syzbot
` (4 preceding siblings ...)
2023-11-26 7:07 ` [PATCH] hwrng: core - fix " Edward Adam Davis
@ 2023-11-29 2:59 ` syzbot
5 siblings, 0 replies; 14+ messages in thread
From: syzbot @ 2023-11-29 2:59 UTC (permalink / raw)
To: linux-kernel
For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org.
***
Subject: [wireless?] WARNING in rate_control_rate_init
Author: eadavis@qq.com
please test WARNING in rate_control_rate_init
#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 6e2332e0ab53
diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 606b1b2e4123..13d52452a124 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -1796,7 +1796,7 @@ static int sta_link_apply_parameters(struct ieee80211_local *local,
!params->supported_rates_len &&
!params->ht_capa && !params->vht_capa &&
!params->he_capa && !params->eht_capa &&
- !params->opmode_notif_used)
+ !params->opmode_notif_used && 0)
return 0;
if (!link || !link_sta)
@@ -1817,6 +1817,7 @@ static int sta_link_apply_parameters(struct ieee80211_local *local,
} else if (new_link) {
return -EINVAL;
}
+ printk("b, %p \n", rcu_access_pointer(sdata->vif.bss_conf.chanctx_conf));
if (params->txpwr_set) {
link_sta->pub->txpwr.type = params->txpwr.type;
@@ -1868,6 +1869,7 @@ static int sta_link_apply_parameters(struct ieee80211_local *local,
params->opmode_notif,
sband->band);
}
+ printk("e, %p \n", rcu_access_pointer(sdata->vif.bss_conf.chanctx_conf));
return ret;
}
@@ -1982,6 +1984,10 @@ static int sta_apply_parameters(struct ieee80211_local *local,
if (params->listen_interval >= 0)
sta->listen_interval = params->listen_interval;
+ printk("b, stp: %d, sa: %d, src: %d\n",
+ test_sta_flag(sta, WLAN_STA_TDLS_PEER),
+ test_sta_flag(sta, WLAN_STA_ASSOC),
+ test_sta_flag(sta, WLAN_STA_RATE_CONTROL));
ret = sta_link_apply_parameters(local, sta, false,
¶ms->link_sta_params);
if (ret)
@@ -1996,6 +2002,10 @@ static int sta_apply_parameters(struct ieee80211_local *local,
if (params->airtime_weight)
sta->airtime_weight = params->airtime_weight;
+ printk("a, stp: %d, sa: %d, src: %d\n",
+ test_sta_flag(sta, WLAN_STA_TDLS_PEER),
+ test_sta_flag(sta, WLAN_STA_ASSOC),
+ test_sta_flag(sta, WLAN_STA_RATE_CONTROL));
/* set the STA state after all sta info from usermode has been set */
if (test_sta_flag(sta, WLAN_STA_TDLS_PEER) ||
set & BIT(NL80211_STA_FLAG_ASSOCIATED)) {
^ permalink raw reply related [flat|nested] 14+ messages in thread
* Re: [PATCH] hwrng: core - fix task hung in hwrng_fillfn
2023-11-26 7:07 ` [PATCH] hwrng: core - fix " Edward Adam Davis
@ 2023-12-01 9:56 ` Herbert Xu
2023-12-01 11:37 ` Edward Adam Davis
0 siblings, 1 reply; 14+ messages in thread
From: Herbert Xu @ 2023-12-01 9:56 UTC (permalink / raw)
To: Edward Adam Davis
Cc: syzbot+c52ab18308964d248092, davem, linux-crypto, linux-kernel,
olivia, syzkaller-bugs
Edward Adam Davis <eadavis@qq.com> wrote:
>
> diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
> index 420f155d251f..7323ddc958ce 100644
> --- a/drivers/char/hw_random/core.c
> +++ b/drivers/char/hw_random/core.c
> @@ -225,17 +225,18 @@ static ssize_t rng_dev_read(struct file *filp, char __user *buf,
> goto out;
> }
>
> - if (mutex_lock_interruptible(&reading_mutex)) {
> - err = -ERESTARTSYS;
> - goto out_put;
> - }
> if (!data_avail) {
> + if (mutex_lock_interruptible(&reading_mutex)) {
> + err = -ERESTARTSYS;
> + goto out_put;
> + }
> bytes_read = rng_get_data(rng, rng_buffer,
> rng_buffer_size(),
> !(filp->f_flags & O_NONBLOCK));
> + mutex_unlock(&reading_mutex);
> if (bytes_read < 0) {
> err = bytes_read;
> - goto out_unlock_reading;
> + goto out_put;
> }
> data_avail = bytes_read;
> }
Does this change anything at all? Please explain why it was holding
this lock for 143 seconds in the first place. If it's doing it in
rng_get_data, then your change has zero effect.
> @@ -501,7 +499,10 @@ static int hwrng_fillfn(void *unused)
> rng = get_current_rng();
> if (IS_ERR(rng) || !rng)
> break;
> - mutex_lock(&reading_mutex);
> + if (mutex_lock_interruptible(&reading_mutex)) {
> + put_rng(rng);
> + return -ERESTARTSYS;
> + }
No this is just the symptom. The real problem is why is the driver
spending 143 seconds in rng_get_data?
Cheers,
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] hwrng: core - fix task hung in hwrng_fillfn
2023-12-01 9:56 ` Herbert Xu
@ 2023-12-01 11:37 ` Edward Adam Davis
2023-12-01 11:41 ` Herbert Xu
0 siblings, 1 reply; 14+ messages in thread
From: Edward Adam Davis @ 2023-12-01 11:37 UTC (permalink / raw)
To: herbert
Cc: davem, eadavis, linux-crypto, linux-kernel, olivia,
syzbot+c52ab18308964d248092, syzkaller-bugs
On Fri, 1 Dec 2023 17:56:59 +0800, Herbert Xu <herbert@gondor.apana.org.au> wrote:
> > diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
> > index 420f155d251f..7323ddc958ce 100644
> > --- a/drivers/char/hw_random/core.c
> > +++ b/drivers/char/hw_random/core.c
> > @@ -225,17 +225,18 @@ static ssize_t rng_dev_read(struct file *filp, char __user *buf,
> > goto out;
> > }
> >
> > - if (mutex_lock_interruptible(&reading_mutex)) {
> > - err = -ERESTARTSYS;
> > - goto out_put;
> > - }
> > if (!data_avail) {
> > + if (mutex_lock_interruptible(&reading_mutex)) {
> > + err = -ERESTARTSYS;
> > + goto out_put;
> > + }
> > bytes_read = rng_get_data(rng, rng_buffer,
> > rng_buffer_size(),
> > !(filp->f_flags & O_NONBLOCK));
> > + mutex_unlock(&reading_mutex);
> > if (bytes_read < 0) {
> > err = bytes_read;
> > - goto out_unlock_reading;
> > + goto out_put;
> > }
> > data_avail = bytes_read;
> > }
>
> Does this change anything at all? Please explain why it was holding
> this lock for 143 seconds in the first place. If it's doing it in
> rng_get_data, then your change has zero effect.
Reduce the scope of critical zone protection.
The original critical zone contains a too large range, especially like
copy_to_user() should not be included in the critical zone.
>
> > @@ -501,7 +499,10 @@ static int hwrng_fillfn(void *unused)
> > rng = get_current_rng();
> > if (IS_ERR(rng) || !rng)
> > break;
> > - mutex_lock(&reading_mutex);
> > + if (mutex_lock_interruptible(&reading_mutex)) {
> > + put_rng(rng);
> > + return -ERESTARTSYS;
> > + }
>
> No this is just the symptom. The real problem is why is the driver
> spending 143 seconds in rng_get_data?
In the second version of the patch, I have removed the fix in hwrng_fillfn().
But for some reason, the V2 patch did not appear in the mailing list.
I think it was due to consuming too much time while executing copy_to_user()
that resulted in 143s.
So, I narrowed down the scope of the critical area and moved the code
copy_to_user() out of the critical area.
Edward
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] hwrng: core - fix task hung in hwrng_fillfn
2023-12-01 11:37 ` Edward Adam Davis
@ 2023-12-01 11:41 ` Herbert Xu
2023-12-01 12:34 ` Edward Adam Davis
0 siblings, 1 reply; 14+ messages in thread
From: Herbert Xu @ 2023-12-01 11:41 UTC (permalink / raw)
To: Edward Adam Davis
Cc: davem, linux-crypto, linux-kernel, olivia,
syzbot+c52ab18308964d248092, syzkaller-bugs
On Fri, Dec 01, 2023 at 07:37:39PM +0800, Edward Adam Davis wrote:
>
> Reduce the scope of critical zone protection.
> The original critical zone contains a too large range, especially like
> copy_to_user() should not be included in the critical zone.
Which part in particular is taking 143 seconds? The buffer is
only 128 bytes long. Why is a 128-byte copy taking 143 seconds,
even with a page fault?
Cheers,
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] hwrng: core - fix task hung in hwrng_fillfn
2023-12-01 11:41 ` Herbert Xu
@ 2023-12-01 12:34 ` Edward Adam Davis
2023-12-01 23:38 ` Herbert Xu
0 siblings, 1 reply; 14+ messages in thread
From: Edward Adam Davis @ 2023-12-01 12:34 UTC (permalink / raw)
To: herbert
Cc: davem, eadavis, linux-crypto, linux-kernel, olivia,
syzbot+c52ab18308964d248092, syzkaller-bugs
On Fri, 1 Dec 2023 19:41:11 +0800, Herbert Xu wrote:
> >
> > Reduce the scope of critical zone protection.
> > The original critical zone contains a too large range, especially like
> > copy_to_user() should not be included in the critical zone.
>
> Which part in particular is taking 143 seconds? The buffer is
> only 128 bytes long. Why is a 128-byte copy taking 143 seconds,
> even with a page fault?
According to splat, after a page fault occurred, the attempt to retrieve
rcu_read_lock() failed, resulting in a timeout of 143s. This is my speculation.
Edward
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] hwrng: core - fix task hung in hwrng_fillfn
2023-12-01 12:34 ` Edward Adam Davis
@ 2023-12-01 23:38 ` Herbert Xu
2023-12-02 1:01 ` [PATCH] hwrng: core - Fix page fault dead lock on mmap-ed hwrng Herbert Xu
0 siblings, 1 reply; 14+ messages in thread
From: Herbert Xu @ 2023-12-01 23:38 UTC (permalink / raw)
To: Edward Adam Davis
Cc: davem, linux-crypto, linux-kernel, olivia,
syzbot+c52ab18308964d248092, syzkaller-bugs
On Fri, Dec 01, 2023 at 08:34:12PM +0800, Edward Adam Davis wrote:
>
> According to splat, after a page fault occurred, the attempt to retrieve
> rcu_read_lock() failed, resulting in a timeout of 143s. This is my speculation.
Oh I see what's going on. The reproducer is mapping /dev/hwrng, so
the write to user-space is then triggering another read which then
dead-locks.
Let me think about this.
Thanks,
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
^ permalink raw reply [flat|nested] 14+ messages in thread
* [PATCH] hwrng: core - Fix page fault dead lock on mmap-ed hwrng
2023-12-01 23:38 ` Herbert Xu
@ 2023-12-02 1:01 ` Herbert Xu
2023-12-12 14:03 ` PrasannaKumar Muralidharan
0 siblings, 1 reply; 14+ messages in thread
From: Herbert Xu @ 2023-12-02 1:01 UTC (permalink / raw)
To: Edward Adam Davis
Cc: davem, linux-crypto, linux-kernel, olivia,
syzbot+c52ab18308964d248092, syzkaller-bugs, Ian Molton,
Rusty Russell
There is a dead-lock in the hwrng device read path. This triggers
when the user reads from /dev/hwrng into memory also mmap-ed from
/dev/hwrng. The resulting page fault triggers a recursive read
which then dead-locks.
Fix this by using a stack buffer when calling copy_to_user.
Reported-by: Edward Adam Davis <eadavis@qq.com>
Reported-by: syzbot+c52ab18308964d248092@syzkaller.appspotmail.com
Fixes: 9996508b3353 ("hwrng: core - Replace u32 in driver API with byte array")
Cc: <stable@vger.kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
index 420f155d251f..a3bbdd6e60fc 100644
--- a/drivers/char/hw_random/core.c
+++ b/drivers/char/hw_random/core.c
@@ -23,10 +23,13 @@
#include <linux/sched.h>
#include <linux/sched/signal.h>
#include <linux/slab.h>
+#include <linux/string.h>
#include <linux/uaccess.h>
#define RNG_MODULE_NAME "hw_random"
+#define RNG_BUFFER_SIZE (SMP_CACHE_BYTES < 32 ? 32 : SMP_CACHE_BYTES)
+
static struct hwrng *current_rng;
/* the current rng has been explicitly chosen by user via sysfs */
static int cur_rng_set_by_user;
@@ -58,7 +61,7 @@ static inline int rng_get_data(struct hwrng *rng, u8 *buffer, size_t size,
static size_t rng_buffer_size(void)
{
- return SMP_CACHE_BYTES < 32 ? 32 : SMP_CACHE_BYTES;
+ return RNG_BUFFER_SIZE;
}
static void add_early_randomness(struct hwrng *rng)
@@ -209,6 +212,7 @@ static inline int rng_get_data(struct hwrng *rng, u8 *buffer, size_t size,
static ssize_t rng_dev_read(struct file *filp, char __user *buf,
size_t size, loff_t *offp)
{
+ u8 buffer[RNG_BUFFER_SIZE];
ssize_t ret = 0;
int err = 0;
int bytes_read, len;
@@ -236,34 +240,37 @@ static ssize_t rng_dev_read(struct file *filp, char __user *buf,
if (bytes_read < 0) {
err = bytes_read;
goto out_unlock_reading;
- }
- data_avail = bytes_read;
- }
-
- if (!data_avail) {
- if (filp->f_flags & O_NONBLOCK) {
+ } else if (bytes_read == 0 &&
+ (filp->f_flags & O_NONBLOCK)) {
err = -EAGAIN;
goto out_unlock_reading;
}
- } else {
- len = data_avail;
+
+ data_avail = bytes_read;
+ }
+
+ len = data_avail;
+ if (len) {
if (len > size)
len = size;
data_avail -= len;
- if (copy_to_user(buf + ret, rng_buffer + data_avail,
- len)) {
+ memcpy(buffer, rng_buffer + data_avail, len);
+ }
+ mutex_unlock(&reading_mutex);
+ put_rng(rng);
+
+ if (len) {
+ if (copy_to_user(buf + ret, buffer, len)) {
err = -EFAULT;
- goto out_unlock_reading;
+ goto out;
}
size -= len;
ret += len;
}
- mutex_unlock(&reading_mutex);
- put_rng(rng);
if (need_resched())
schedule_timeout_interruptible(1);
@@ -274,6 +281,7 @@ static ssize_t rng_dev_read(struct file *filp, char __user *buf,
}
}
out:
+ memzero_explicit(buffer, sizeof(buffer));
return ret ? : err;
out_unlock_reading:
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
^ permalink raw reply related [flat|nested] 14+ messages in thread
* Re: [PATCH] hwrng: core - Fix page fault dead lock on mmap-ed hwrng
2023-12-02 1:01 ` [PATCH] hwrng: core - Fix page fault dead lock on mmap-ed hwrng Herbert Xu
@ 2023-12-12 14:03 ` PrasannaKumar Muralidharan
0 siblings, 0 replies; 14+ messages in thread
From: PrasannaKumar Muralidharan @ 2023-12-12 14:03 UTC (permalink / raw)
To: Herbert Xu
Cc: Edward Adam Davis, davem, linux-crypto, linux-kernel, olivia,
syzbot+c52ab18308964d248092, syzkaller-bugs, Ian Molton,
Rusty Russell
On Sat, 2 Dec 2023 at 08:05, Herbert Xu <herbert@gondor.apana.org.au> wrote:
>
> There is a dead-lock in the hwrng device read path. This triggers
> when the user reads from /dev/hwrng into memory also mmap-ed from
> /dev/hwrng. The resulting page fault triggers a recursive read
> which then dead-locks.
>
> Fix this by using a stack buffer when calling copy_to_user.
>
> Reported-by: Edward Adam Davis <eadavis@qq.com>
> Reported-by: syzbot+c52ab18308964d248092@syzkaller.appspotmail.com
> Fixes: 9996508b3353 ("hwrng: core - Replace u32 in driver API with byte array")
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
>
> diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
> index 420f155d251f..a3bbdd6e60fc 100644
> --- a/drivers/char/hw_random/core.c
> +++ b/drivers/char/hw_random/core.c
> @@ -23,10 +23,13 @@
> #include <linux/sched.h>
> #include <linux/sched/signal.h>
> #include <linux/slab.h>
> +#include <linux/string.h>
> #include <linux/uaccess.h>
>
> #define RNG_MODULE_NAME "hw_random"
>
> +#define RNG_BUFFER_SIZE (SMP_CACHE_BYTES < 32 ? 32 : SMP_CACHE_BYTES)
> +
> static struct hwrng *current_rng;
> /* the current rng has been explicitly chosen by user via sysfs */
> static int cur_rng_set_by_user;
> @@ -58,7 +61,7 @@ static inline int rng_get_data(struct hwrng *rng, u8 *buffer, size_t size,
>
> static size_t rng_buffer_size(void)
> {
> - return SMP_CACHE_BYTES < 32 ? 32 : SMP_CACHE_BYTES;
> + return RNG_BUFFER_SIZE;
> }
>
> static void add_early_randomness(struct hwrng *rng)
> @@ -209,6 +212,7 @@ static inline int rng_get_data(struct hwrng *rng, u8 *buffer, size_t size,
> static ssize_t rng_dev_read(struct file *filp, char __user *buf,
> size_t size, loff_t *offp)
> {
> + u8 buffer[RNG_BUFFER_SIZE];
> ssize_t ret = 0;
> int err = 0;
> int bytes_read, len;
> @@ -236,34 +240,37 @@ static ssize_t rng_dev_read(struct file *filp, char __user *buf,
> if (bytes_read < 0) {
> err = bytes_read;
> goto out_unlock_reading;
> - }
> - data_avail = bytes_read;
> - }
> -
> - if (!data_avail) {
> - if (filp->f_flags & O_NONBLOCK) {
> + } else if (bytes_read == 0 &&
> + (filp->f_flags & O_NONBLOCK)) {
> err = -EAGAIN;
> goto out_unlock_reading;
> }
> - } else {
> - len = data_avail;
> +
> + data_avail = bytes_read;
> + }
> +
> + len = data_avail;
> + if (len) {
> if (len > size)
> len = size;
>
> data_avail -= len;
>
> - if (copy_to_user(buf + ret, rng_buffer + data_avail,
> - len)) {
> + memcpy(buffer, rng_buffer + data_avail, len);
> + }
> + mutex_unlock(&reading_mutex);
> + put_rng(rng);
> +
> + if (len) {
> + if (copy_to_user(buf + ret, buffer, len)) {
> err = -EFAULT;
> - goto out_unlock_reading;
> + goto out;
> }
>
> size -= len;
> ret += len;
> }
>
> - mutex_unlock(&reading_mutex);
> - put_rng(rng);
>
> if (need_resched())
> schedule_timeout_interruptible(1);
> @@ -274,6 +281,7 @@ static ssize_t rng_dev_read(struct file *filp, char __user *buf,
> }
> }
> out:
> + memzero_explicit(buffer, sizeof(buffer));
> return ret ? : err;
>
> out_unlock_reading:
> --
> Email: Herbert Xu <herbert@gondor.apana.org.au>
> Home Page: http://gondor.apana.org.au/~herbert/
> PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
>
Reviewed-by: PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>
Regards,
PrasannaKumar
^ permalink raw reply [flat|nested] 14+ messages in thread
end of thread, other threads:[~2023-12-12 14:03 UTC | newest]
Thread overview: 14+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-11-25 13:21 [syzbot] [crypto?] INFO: task hung in hwrng_fillfn syzbot
2023-11-26 3:52 ` syzbot
2023-11-26 4:05 ` syzbot
2023-11-26 4:06 ` syzbot
2023-11-26 5:35 ` syzbot
2023-11-26 7:07 ` [PATCH] hwrng: core - fix " Edward Adam Davis
2023-12-01 9:56 ` Herbert Xu
2023-12-01 11:37 ` Edward Adam Davis
2023-12-01 11:41 ` Herbert Xu
2023-12-01 12:34 ` Edward Adam Davis
2023-12-01 23:38 ` Herbert Xu
2023-12-02 1:01 ` [PATCH] hwrng: core - Fix page fault dead lock on mmap-ed hwrng Herbert Xu
2023-12-12 14:03 ` PrasannaKumar Muralidharan
2023-11-29 2:59 ` [syzbot] [wireless?] WARNING in rate_control_rate_init syzbot
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