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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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a9ce385344
dm looks up the table for IO based on the request type, with an
assumption that if the request is marked REQ_NOWAIT, it's fine to
attempt to submit that IO while under RCU read lock protection. This
is not OK, as REQ_NOWAIT just means that we should not be sleeping
waiting on other IO, it does not mean that we can't potentially
schedule.
A simple test case demonstrates this quite nicely:
int main(int argc, char *argv[])
{
struct iovec iov;
int fd;
fd = open("/dev/dm-0", O_RDONLY | O_DIRECT);
posix_memalign(&iov.iov_base, 4096, 4096);
iov.iov_len = 4096;
preadv2(fd, &iov, 1, 0, RWF_NOWAIT);
return 0;
}
which will instantly spew:
BUG: sleeping function called from invalid context at include/linux/sched/mm.h:306
in_atomic(): 0, irqs_disabled(): 0, non_block: 0, pid: 5580, name: dm-nowait
preempt_count: 0, expected: 0
RCU nest depth: 1, expected: 0
INFO: lockdep is turned off.
CPU: 7 PID: 5580 Comm: dm-nowait Not tainted 6.6.0-rc1-g39956d2dcd81 #132
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
<TASK>
dump_stack_lvl+0x11d/0x1b0
__might_resched+0x3c3/0x5e0
? preempt_count_sub+0x150/0x150
mempool_alloc+0x1e2/0x390
? mempool_resize+0x7d0/0x7d0
? lock_sync+0x190/0x190
? lock_release+0x4b7/0x670
? internal_get_user_pages_fast+0x868/0x2d40
bio_alloc_bioset+0x417/0x8c0
? bvec_alloc+0x200/0x200
? internal_get_user_pages_fast+0xb8c/0x2d40
bio_alloc_clone+0x53/0x100
dm_submit_bio+0x27f/0x1a20
? lock_release+0x4b7/0x670
? blk_try_enter_queue+0x1a0/0x4d0
? dm_dax_direct_access+0x260/0x260
? rcu_is_watching+0x12/0xb0
? blk_try_enter_queue+0x1cc/0x4d0
__submit_bio+0x239/0x310
? __bio_queue_enter+0x700/0x700
? kvm_clock_get_cycles+0x40/0x60
? ktime_get+0x285/0x470
submit_bio_noacct_nocheck+0x4d9/0xb80
? should_fail_request+0x80/0x80
? preempt_count_sub+0x150/0x150
? lock_release+0x4b7/0x670
? __bio_add_page+0x143/0x2d0
? iov_iter_revert+0x27/0x360
submit_bio_noacct+0x53e/0x1b30
submit_bio_wait+0x10a/0x230
? submit_bio_wait_endio+0x40/0x40
__blkdev_direct_IO_simple+0x4f8/0x780
? blkdev_bio_end_io+0x4c0/0x4c0
? stack_trace_save+0x90/0xc0
? __bio_clone+0x3c0/0x3c0
? lock_release+0x4b7/0x670
? lock_sync+0x190/0x190
? atime_needs_update+0x3bf/0x7e0
? timestamp_truncate+0x21b/0x2d0
? inode_owner_or_capable+0x240/0x240
blkdev_direct_IO.part.0+0x84a/0x1810
? rcu_is_watching+0x12/0xb0
? lock_release+0x4b7/0x670
? blkdev_read_iter+0x40d/0x530
? reacquire_held_locks+0x4e0/0x4e0
? __blkdev_direct_IO_simple+0x780/0x780
? rcu_is_watching+0x12/0xb0
? __mark_inode_dirty+0x297/0xd50
? preempt_count_add+0x72/0x140
blkdev_read_iter+0x2a4/0x530
do_iter_readv_writev+0x2f2/0x3c0
? generic_copy_file_range+0x1d0/0x1d0
? fsnotify_perm.part.0+0x25d/0x630
? security_file_permission+0xd8/0x100
do_iter_read+0x31b/0x880
? import_iovec+0x10b/0x140
vfs_readv+0x12d/0x1a0
? vfs_iter_read+0xb0/0xb0
? rcu_is_watching+0x12/0xb0
? rcu_is_watching+0x12/0xb0
? lock_release+0x4b7/0x670
do_preadv+0x1b3/0x260
? do_readv+0x370/0x370
__x64_sys_preadv2+0xef/0x150
do_syscall_64+0x39/0xb0
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f5af41ad806
Code: 41 54 41 89 fc 55 44 89 c5 53 48 89 cb 48 83 ec 18 80 3d e4 dd 0d 00 00 74 7a 45 89 c1 49 89 ca 45 31 c0 b8 47 01 00 00 0f 05 <48> 3d 00 f0 ff ff 0f 87 be 00 00 00 48 85 c0 79 4a 48 8b 0d da 55
RSP: 002b:00007ffd3145c7f0 EFLAGS: 00000246 ORIG_RAX: 0000000000000147
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f5af41ad806
RDX: 0000000000000001 RSI: 00007ffd3145c850 RDI: 0000000000000003
RBP: 0000000000000008 R08: 0000000000000000 R09: 0000000000000008
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 00007ffd3145c850 R14: 000055f5f0431dd8 R15: 0000000000000001
</TASK>
where in fact it is dm itself that attempts to allocate a bio clone with
GFP_NOIO under the rcu read lock, regardless of the request type.
Fix this by getting rid of the special casing for REQ_NOWAIT, and just
use the normal SRCU protected table lookup. Get rid of the bio based
table locking helpers at the same time, as they are now unused.
Cc: stable@vger.kernel.org
Fixes:
|
||
|---|---|---|
| .. | ||
| accel | ||
| accessibility | ||
| acpi | ||
| amba | ||
| android | ||
| ata | ||
| atm | ||
| auxdisplay | ||
| base | ||
| bcma | ||
| block | ||
| bluetooth | ||
| bus | ||
| cache | ||
| cdrom | ||
| cdx | ||
| char | ||
| clk | ||
| clocksource | ||
| comedi | ||
| connector | ||
| counter | ||
| cpufreq | ||
| cpuidle | ||
| crypto | ||
| cxl | ||
| dax | ||
| dca | ||
| devfreq | ||
| dio | ||
| dma | ||
| dma-buf | ||
| edac | ||
| eisa | ||
| extcon | ||
| firewire | ||
| firmware | ||
| fpga | ||
| fsi | ||
| genpd | ||
| gnss | ||
| gpio | ||
| gpu | ||
| greybus | ||
| hid | ||
| hsi | ||
| hte | ||
| hv | ||
| hwmon | ||
| hwspinlock | ||
| hwtracing | ||
| i2c | ||
| i3c | ||
| idle | ||
| iio | ||
| infiniband | ||
| input | ||
| interconnect | ||
| iommu | ||
| ipack | ||
| irqchip | ||
| isdn | ||
| leds | ||
| macintosh | ||
| mailbox | ||
| mcb | ||
| md | ||
| media | ||
| memory | ||
| memstick | ||
| message | ||
| mfd | ||
| misc | ||
| mmc | ||
| most | ||
| mtd | ||
| mux | ||
| net | ||
| nfc | ||
| ntb | ||
| nubus | ||
| nvdimm | ||
| nvme | ||
| nvmem | ||
| of | ||
| opp | ||
| parisc | ||
| parport | ||
| pci | ||
| pcmcia | ||
| peci | ||
| perf | ||
| phy | ||
| pinctrl | ||
| platform | ||
| pnp | ||
| power | ||
| powercap | ||
| pps | ||
| ps3 | ||
| ptp | ||
| pwm | ||
| rapidio | ||
| ras | ||
| regulator | ||
| remoteproc | ||
| reset | ||
| rpmsg | ||
| rtc | ||
| s390 | ||
| sbus | ||
| scsi | ||
| sh | ||
| siox | ||
| slimbus | ||
| soc | ||
| soundwire | ||
| spi | ||
| spmi | ||
| ssb | ||
| staging | ||
| target | ||
| tc | ||
| tee | ||
| thermal | ||
| thunderbolt | ||
| tty | ||
| ufs | ||
| uio | ||
| usb | ||
| vdpa | ||
| vfio | ||
| vhost | ||
| video | ||
| virt | ||
| virtio | ||
| vlynq | ||
| w1 | ||
| watchdog | ||
| xen | ||
| zorro | ||
| Kconfig | ||
| Makefile | ||