RE: [PATCH v3] scsi: avoid potential deadloop in iscsi_if_rx func
Hi, > On 11/12/19 5:37 PM, Martin K. Petersen wrote: > > > >> In iscsi_if_rx func, after receiving one request through > >> iscsi_if_recv_msg func, iscsi_if_send_reply will be called to try to > >> reply the request in do-loop. If the return of iscsi_if_send_reply > >> func return -EAGAIN all the time, one deadloop will occur. > >> > >> For example, a client only send msg without calling recvmsg func, > >> then it will result in the watchdog soft lockup. > >> The details are given as follows, > > > > Lee/Chris/Ulrich: Please review! > > > > > Okay, after looking again at the thread, I do have some additional feedback > for > the patch submitter. > > You should put your "changes in V2, V3, ..." above the patch line (the > "-- " on a line by itself), not as part of the patch. > > Also, as long as you are making one last round of changes, please change > "deadloop" to "deadlock" in your patch subject, as deadloop is not a word. > Okay, I will correct it in V4. > Lastly, the "Suggested-by" lines you added are fine, but that generally means > that person suggested the patch, not changes. For folks that suggest changes, > it's up to them to say they like or do not like your changes after you make > them, > at which point they can add their "Reviewed-by" tag if they wish. > > Please feel free to send your patch to me directly, before publishing, if you > would like a review before publishing again. Okay, Thanks. > > -- > Lee -- You received this message because you are subscribed to the Google Groups "open-iscsi" group. To unsubscribe from this group and stop receiving emails from it, send an email to open-iscsi+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/open-iscsi/EDBAAA0BBBA2AC4E9C8B6B81DEEE1D6915E28CFE%40dggeml505-mbs.china.huawei.com.
Re: [PATCH v3] scsi: avoid potential deadloop in iscsi_if_rx func
On 11/12/19 5:37 PM, Martin K. Petersen wrote: > >> In iscsi_if_rx func, after receiving one request through >> iscsi_if_recv_msg func, iscsi_if_send_reply will be called to try to >> reply the request in do-loop. If the return of iscsi_if_send_reply >> func return -EAGAIN all the time, one deadloop will occur. >> >> For example, a client only send msg without calling recvmsg func, >> then it will result in the watchdog soft lockup. >> The details are given as follows, > > Lee/Chris/Ulrich: Please review! > Okay, after looking again at the thread, I do have some additional feedback for the patch submitter. You should put your "changes in V2, V3, ..." above the patch line (the "-- " on a line by itself), not as part of the patch. Also, as long as you are making one last round of changes, please change "deadloop" to "deadlock" in your patch subject, as deadloop is not a word. Lastly, the "Suggested-by" lines you added are fine, but that generally means that person suggested the patch, not changes. For folks that suggest changes, it's up to them to say they like or do not like your changes after you make them, at which point they can add their "Reviewed-by" tag if they wish. Please feel free to send your patch to me directly, before publishing, if you would like a review before publishing again. -- Lee -- You received this message because you are subscribed to the Google Groups "open-iscsi" group. To unsubscribe from this group and stop receiving emails from it, send an email to open-iscsi+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/open-iscsi/e0ddba45-7fd4-a1e9-b1e8-d59a46316695%40suse.com.
Re: [PATCH v3] scsi: avoid potential deadloop in iscsi_if_rx func
On 11/12/19 5:37 PM, Martin K. Petersen wrote: > >> In iscsi_if_rx func, after receiving one request through >> iscsi_if_recv_msg func, iscsi_if_send_reply will be called to try to >> reply the request in do-loop. If the return of iscsi_if_send_reply >> func return -EAGAIN all the time, one deadloop will occur. >> >> For example, a client only send msg without calling recvmsg func, >> then it will result in the watchdog soft lockup. >> The details are given as follows, > > Lee/Chris/Ulrich: Please review! > I believe I already added my Reviewed-by tag. Do you mean past that? Perhaps I missed something. -- Lee Duncan -- You received this message because you are subscribed to the Google Groups "open-iscsi" group. To unsubscribe from this group and stop receiving emails from it, send an email to open-iscsi+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/open-iscsi/d0d2bcf7-9d9d-40f9-335d-ebcdafdf9969%40suse.com.
Re: [PATCH v3] scsi: avoid potential deadloop in iscsi_if_rx func
> In iscsi_if_rx func, after receiving one request through > iscsi_if_recv_msg func, iscsi_if_send_reply will be called to try to > reply the request in do-loop. If the return of iscsi_if_send_reply > func return -EAGAIN all the time, one deadloop will occur. > > For example, a client only send msg without calling recvmsg func, > then it will result in the watchdog soft lockup. > The details are given as follows, Lee/Chris/Ulrich: Please review! -- Martin K. Petersen Oracle Linux Engineering -- You received this message because you are subscribed to the Google Groups "open-iscsi" group. To unsubscribe from this group and stop receiving emails from it, send an email to open-iscsi+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/open-iscsi/yq18soksgji.fsf%40oracle.com.
Re: [PATCH v3] scsi: avoid potential deadloop in iscsi_if_rx func
Friendly ping...
On 2019/10/31 14:17, wubo (T) wrote:
> From: Bo Wu
>
> In iscsi_if_rx func, after receiving one request through
> iscsi_if_recv_msg func, iscsi_if_send_reply will be called to
> try to reply the request in do-loop. If the return of iscsi_if_send_reply
> func return -EAGAIN all the time, one deadloop will occur.
>
> For example, a client only send msg without calling recvmsg func,
> then it will result in the watchdog soft lockup.
> The details are given as follows,
>
> Details of the special case which can cause deadloop:
>
> sock_fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_ISCSI);
> retval = bind(sock_fd, (struct sock addr*) & src_addr, sizeof(src_addr);
> while (1) {
> state_msg = sendmsg(sock_fd, , 0);
> //Note: recvmsg(sock_fd, , 0) is not processed here.
> }
> close(sock_fd);
>
> watchdog: BUG: soft lockup - CPU#7 stuck for 22s! [netlink_test:253305]
> Sample time: 4000897528 ns(HZ: 250) Sample stat:
> curr: user: 675503481560, nice: 321724050, sys: 448689506750, idle:
> 4654054240530, iowait: 40885550700, irq: 14161174020, softirq: 8104324140,
> st: 0
> deta: user: 0, nice: 0, sys: 3998210100, idle: 0, iowait: 0, irq: 1547170,
> softirq: 242870, st: 0 Sample softirq:
> TIMER:992
> SCHED: 8
> Sample irqstat:
> irq2: delta 1003, curr:3103802, arch_timer
> CPU: 7 PID: 253305 Comm: netlink_test Kdump: loaded Tainted: G OE
>
> Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015
> pstate: 4045 (nZcv daif +PAN -UAO)
> pc : __alloc_skb+0x104/0x1b0
> lr : __alloc_skb+0x9c/0x1b0
> sp : 33603a30
> x29: 33603a30 x28: 02dd
> x27: 800b34ced810 x26: 800ba7569f00
> x25: x24:
> x23: 800f7c43f600 x22: 00480020
> x21: 091d9000 x20: 800b34eff200
> x19: 800ba7569f00 x18:
> x17: x16:
> x15: x14: 0001000101000100
> x13: 00010101 x12: 010101010100
> x11: 0001010101010001 x10: 02dd
> x9 : 33603d58 x8 : 800b34eff400
> x7 : 800ba7569200 x6 : 800b34eff400
> x5 : x4 :
> x3 : x2 : 0001
> x1 : 800b34eff2c0 x0 : 0300 Call trace:
> __alloc_skb+0x104/0x1b0
> iscsi_if_rx+0x144/0x12bc [scsi_transport_iscsi]
> netlink_unicast+0x1e0/0x258
> netlink_sendmsg+0x310/0x378
> sock_sendmsg+0x4c/0x70
> sock_write_iter+0x90/0xf0
> __vfs_write+0x11c/0x190
> vfs_write+0xac/0x1c0
> ksys_write+0x6c/0xd8
> __arm64_sys_write+0x24/0x30
> el0_svc_common+0x78/0x130
> el0_svc_handler+0x38/0x78
> el0_svc+0x8/0xc
>
> Here, we add one limit of retry times in do-loop to avoid the deadloop.
>
> Signed-off-by: Bo Wu
> Reviewed-by: Zhiqiang Liu
> Suggested-by: Lee Duncan
> Suggested-by: Ulrich Windl
> ---
> V3:replace the error with warning as suggested by Ulrich
> V2:add some debug kernel message as suggested by Lee Duncan
>
> Thanks,
> Bo Wu
>
> drivers/scsi/scsi_transport_iscsi.c | 7 +++
> 1 file changed, 7 insertions(+)
>
> diff --git a/drivers/scsi/scsi_transport_iscsi.c
> b/drivers/scsi/scsi_transport_iscsi.c
> index 417b868d8735..ed8d9709b9b9 100644
> --- a/drivers/scsi/scsi_transport_iscsi.c
> +++ b/drivers/scsi/scsi_transport_iscsi.c
> @@ -24,6 +24,8 @@
>
> #define ISCSI_TRANSPORT_VERSION "2.0-870"
>
> +#define ISCSI_SEND_MAX_ALLOWED 10
> +
> #define CREATE_TRACE_POINTS
> #include
>
> @@ -3682,6 +3684,7 @@ iscsi_if_rx(struct sk_buff *skb)
> struct nlmsghdr *nlh;
> struct iscsi_uevent *ev;
> uint32_t group;
> + int retries = ISCSI_SEND_MAX_ALLOWED;
>
> nlh = nlmsg_hdr(skb);
> if (nlh->nlmsg_len < sizeof(*nlh) + sizeof(*ev) ||
> @@ -3712,6 +3715,10 @@ iscsi_if_rx(struct sk_buff *skb)
> break;
> err = iscsi_if_send_reply(portid, nlh->nlmsg_type,
> ev, sizeof(*ev));
> + if (err == -EAGAIN && --retries < 0) {
> + printk(KERN_WARNING "Send reply failed, error
> %d\n", err);
> + break;
> + }
> } while (err < 0 && err != -ECONNREFUSED && err != -ESRCH);
> skb_pull(skb, rlen);
> }
> --
> 1.8.3.1
>
>
> .
>
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