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 @@ -515,7 +515,8 @@ 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; @@ -549,6 +550,11 @@ 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; @@ -631,16 +637,15 @@ 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; }