Now almost all .map_queues() implementation based on managed irq
affinity doesn't update queue mapping and it just retrieves the
old built mapping, so if nr_hw_queues is changed, the mapping talbe
includes stale mapping. And only blk_mq_map_queues() may rebuild
the mapping talbe.
One case is that we limit .nr_hw_queues as 1 in case of kdump kernel.
However, drivers often builds queue mapping before allocating tagset
via pci_alloc_irq_vectors_affinity(), but set->nr_hw_queues can be set
as 1 in case of kdump kernel, so wrong queue mapping is used, and
kernel panic[1] is observed during booting.
This patch fixes the kernel panic triggerd on nvme by rebulding the
mapping table via blk_mq_map_queues().
[1] kernel panic log
[ 4.438371] nvme nvme0: 16/0/0 default/read/poll queues
[ 4.443277] BUG: unable to handle kernel NULL pointer dereference at 0000000000000098
[ 4.444681] PGD 0 P4D 0
[ 4.445367] Oops: 0000 [#1] SMP NOPTI
[ 4.446342] CPU: 3 PID: 201 Comm: kworker/u33:10 Not tainted 4.20.0-rc5-00664-g5eb02f7ee1eb-dirty #459
[ 4.447630] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.10.2-2.fc27 04/01/2014
[ 4.448689] Workqueue: nvme-wq nvme_scan_work [nvme_core]
[ 4.449368] RIP: 0010:blk_mq_map_swqueue+0xfb/0x222
[ 4.450596] Code: 04 f5 20 28 ef 81 48 89 c6 39 55 30 76 93 89 d0 48 c1 e0 04 48 03 83 f8 05 00 00 48 8b 00 42 8b 3c 28 48 8b 43 58 48 8b 04 f8 <48> 8b b8 98 00 00 00 4c 0f a3 37 72 42 f0 4c 0f ab 37 66 8b b8 f6
[ 4.453132] RSP: 0018:ffffc900023b3cd8 EFLAGS: 00010286
[ 4.454061] RAX: 0000000000000000 RBX: ffff888174448000 RCX: 0000000000000001
[ 4.456480] RDX: 0000000000000001 RSI: ffffe8feffc506c0 RDI: 0000000000000001
[ 4.458750] RBP: ffff88810722d008 R08: ffff88817647a880 R09: 0000000000000002
[ 4.464580] R10: ffffc900023b3c10 R11: 0000000000000004 R12: ffff888174448538
[ 4.467803] R13: 0000000000000004 R14: 0000000000000001 R15: 0000000000000001
[ 4.469220] FS: 0000000000000000(0000) GS:ffff88817bac0000(0000) knlGS:0000000000000000
[ 4.471554] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 4.472464] CR2: 0000000000000098 CR3: 0000000174e4e001 CR4: 0000000000760ee0
[ 4.474264] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 4.476007] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 4.477061] PKRU: 55555554
[ 4.477464] Call Trace:
[ 4.478731] blk_mq_init_allocated_queue+0x36a/0x3ad
[ 4.479595] blk_mq_init_queue+0x32/0x4e
[ 4.480178] nvme_validate_ns+0x98/0x623 [nvme_core]
[ 4.480963] ? nvme_submit_sync_cmd+0x1b/0x20 [nvme_core]
[ 4.481685] ? nvme_identify_ctrl.isra.8+0x70/0xa0 [nvme_core]
[ 4.482601] nvme_scan_work+0x23a/0x29b [nvme_core]
[ 4.483269] ? _raw_spin_unlock_irqrestore+0x25/0x38
[ 4.483930] ? try_to_wake_up+0x38d/0x3b3
[ 4.484478] ? process_one_work+0x179/0x2fc
[ 4.485118] process_one_work+0x1d3/0x2fc
[ 4.485655] ? rescuer_thread+0x2ae/0x2ae
[ 4.486196] worker_thread+0x1e9/0x2be
[ 4.486841] kthread+0x115/0x11d
[ 4.487294] ? kthread_park+0x76/0x76
[ 4.487784] ret_from_fork+0x3a/0x50
[ 4.488322] Modules linked in: nvme nvme_core qemu_fw_cfg virtio_scsi ip_tables
[ 4.489428] Dumping ftrace buffer:
[ 4.489939] (ftrace buffer empty)
[ 4.490492] CR2: 0000000000000098
[ 4.491052] ---[ end trace 03cd268ad5a86ff7 ]---
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: linux-nvme@xxxxxxxxxxxxxxxxxxx
Cc: David Milburn <dmilburn@xxxxxxxxxx>
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
---
block/blk-mq.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 900550594651..a3e463a726a6 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -38,6 +38,11 @@
#include "blk-mq-sched.h"
#include "blk-rq-qos.h"
+static inline bool blk_mq_kdump_kernel(void)
+{
+ return !!is_kdump_kernel();
+}
+
static void blk_mq_poll_stats_start(struct request_queue *q);
static void blk_mq_poll_stats_fn(struct blk_stat_callback *cb);
@@ -2960,7 +2965,7 @@ static int blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set)
static int blk_mq_update_queue_map(struct blk_mq_tag_set *set)
{
- if (set->ops->map_queues) {
+ if (set->ops->map_queues && !blk_mq_kdump_kernel()) {
int i;
/*
@@ -3028,8 +3033,9 @@ int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set)
* memory constrained environment. Limit us to 1 queue and
* 64 tags to prevent using too much memory.
*/
- if (is_kdump_kernel()) {
+ if (blk_mq_kdump_kernel()) {
set->nr_hw_queues = 1;
+ set->nr_maps = 1;
set->queue_depth = min(64U, set->queue_depth);
}
/*
@@ -3051,7 +3057,7 @@ int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set)
GFP_KERNEL, set->numa_node);
if (!set->map[i].mq_map)
goto out_free_mq_map;
- set->map[i].nr_queues = set->nr_hw_queues;
+ set->map[i].nr_queues = blk_mq_kdump_kernel() ? 1 : set->nr_hw_queues;
}
ret = blk_mq_update_queue_map(set);
--
2.9.5
