| From 936bd03405fc83ba039d42bc93ffd4b88418f1d3 Mon Sep 17 00:00:00 2001 |
| From: John Meneghini <jmeneghi@redhat.com> |
| Date: Mon, 24 Jan 2022 09:51:10 -0500 |
| Subject: scsi: bnx2fc: Make bnx2fc_recv_frame() mp safe |
| |
| From: John Meneghini <jmeneghi@redhat.com> |
| |
| commit 936bd03405fc83ba039d42bc93ffd4b88418f1d3 upstream. |
| |
| Running tests with a debug kernel shows that bnx2fc_recv_frame() is |
| modifying the per_cpu lport stats counters in a non-mpsafe way. Just boot |
| a debug kernel and run the bnx2fc driver with the hardware enabled. |
| |
| [ 1391.699147] BUG: using smp_processor_id() in preemptible [00000000] code: bnx2fc_ |
| [ 1391.699160] caller is bnx2fc_recv_frame+0xbf9/0x1760 [bnx2fc] |
| [ 1391.699174] CPU: 2 PID: 4355 Comm: bnx2fc_l2_threa Kdump: loaded Tainted: G B |
| [ 1391.699180] Hardware name: HP ProLiant DL120 G7, BIOS J01 07/01/2013 |
| [ 1391.699183] Call Trace: |
| [ 1391.699188] dump_stack_lvl+0x57/0x7d |
| [ 1391.699198] check_preemption_disabled+0xc8/0xd0 |
| [ 1391.699205] bnx2fc_recv_frame+0xbf9/0x1760 [bnx2fc] |
| [ 1391.699215] ? do_raw_spin_trylock+0xb5/0x180 |
| [ 1391.699221] ? bnx2fc_npiv_create_vports.isra.0+0x4e0/0x4e0 [bnx2fc] |
| [ 1391.699229] ? bnx2fc_l2_rcv_thread+0xb7/0x3a0 [bnx2fc] |
| [ 1391.699240] bnx2fc_l2_rcv_thread+0x1af/0x3a0 [bnx2fc] |
| [ 1391.699250] ? bnx2fc_ulp_init+0xc0/0xc0 [bnx2fc] |
| [ 1391.699258] kthread+0x364/0x420 |
| [ 1391.699263] ? _raw_spin_unlock_irq+0x24/0x50 |
| [ 1391.699268] ? set_kthread_struct+0x100/0x100 |
| [ 1391.699273] ret_from_fork+0x22/0x30 |
| |
| Restore the old get_cpu/put_cpu code with some modifications to reduce the |
| size of the critical section. |
| |
| Link: https://lore.kernel.org/r/20220124145110.442335-1-jmeneghi@redhat.com |
| Fixes: d576a5e80cd0 ("bnx2fc: Improve stats update mechanism") |
| Tested-by: Guangwu Zhang <guazhang@redhat.com> |
| Acked-by: Saurav Kashyap <skashyap@marvell.com> |
| Signed-off-by: John Meneghini <jmeneghi@redhat.com> |
| Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| drivers/scsi/bnx2fc/bnx2fc_fcoe.c | 21 +++++++++++++-------- |
| 1 file changed, 13 insertions(+), 8 deletions(-) |
| |
| --- a/drivers/scsi/bnx2fc/bnx2fc_fcoe.c |
| +++ b/drivers/scsi/bnx2fc/bnx2fc_fcoe.c |
| @@ -506,7 +506,8 @@ static int bnx2fc_l2_rcv_thread(void *ar |
| |
| static void bnx2fc_recv_frame(struct sk_buff *skb) |
| { |
| - u32 fr_len; |
| + u64 crc_err; |
| + u32 fr_len, fr_crc; |
| struct fc_lport *lport; |
| struct fcoe_rcv_info *fr; |
| struct fc_stats *stats; |
| @@ -540,6 +541,11 @@ static void bnx2fc_recv_frame(struct sk_ |
| skb_pull(skb, sizeof(struct fcoe_hdr)); |
| fr_len = skb->len - sizeof(struct fcoe_crc_eof); |
| |
| + stats = per_cpu_ptr(lport->stats, get_cpu()); |
| + stats->RxFrames++; |
| + stats->RxWords += fr_len / FCOE_WORD_TO_BYTE; |
| + put_cpu(); |
| + |
| fp = (struct fc_frame *)skb; |
| fc_frame_init(fp); |
| fr_dev(fp) = lport; |
| @@ -622,16 +628,15 @@ static void bnx2fc_recv_frame(struct sk_ |
| return; |
| } |
| |
| - stats = per_cpu_ptr(lport->stats, smp_processor_id()); |
| - stats->RxFrames++; |
| - stats->RxWords += fr_len / FCOE_WORD_TO_BYTE; |
| + fr_crc = le32_to_cpu(fr_crc(fp)); |
| |
| - if (le32_to_cpu(fr_crc(fp)) != |
| - ~crc32(~0, skb->data, fr_len)) { |
| - if (stats->InvalidCRCCount < 5) |
| + if (unlikely(fr_crc != ~crc32(~0, skb->data, fr_len))) { |
| + stats = per_cpu_ptr(lport->stats, get_cpu()); |
| + crc_err = (stats->InvalidCRCCount++); |
| + put_cpu(); |
| + if (crc_err < 5) |
| printk(KERN_WARNING PFX "dropping frame with " |
| "CRC error\n"); |
| - stats->InvalidCRCCount++; |
| kfree_skb(skb); |
| return; |
| } |