| Message ID | 1540837916-14356-1-git-send-email-manjunath.b.patil@oracle.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | xen-blkfront: fix kernel panic with negotiate_mq error path | expand |
On 29/10/2018 19:31, Manjunath Patil wrote: > info->nr_rings isn't adjusted in case of ENOMEM error from > negotiate_mq(). This leads to kernel panic in error path. > > Typical call stack involving panic - > #8 page_fault at ffffffff8175936f > [exception RIP: blkif_free_ring+33] > RIP: ffffffffa0149491 RSP: ffff8804f7673c08 RFLAGS: 00010292 > ... > #9 blkif_free at ffffffffa0149aaa [xen_blkfront] > #10 talk_to_blkback at ffffffffa014c8cd [xen_blkfront] > #11 blkback_changed at ffffffffa014ea8b [xen_blkfront] > #12 xenbus_otherend_changed at ffffffff81424670 > #13 backend_changed at ffffffff81426dc3 > #14 xenwatch_thread at ffffffff81422f29 > #15 kthread at ffffffff810abe6a > #16 ret_from_fork at ffffffff81754078 > > Though either of my changes avoid the panic, I included both the > changes. This issue got introduced with "7ed8ce1 xen-blkfront: move > negotiate_mq to cover all cases of new VBDs" Please us the correct format for specifying another commit. > Signed-off-by: Manjunath Patil <manjunath.b.patil@oracle.com> Can you please add a "Fixes:" tag and "Cc: stable@vger.kernel.org" ? > --- > drivers/block/xen-blkfront.c | 7 +++++-- > 1 files changed, 5 insertions(+), 2 deletions(-) > > diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c > index 429d201..dc8fe25 100644 > --- a/drivers/block/xen-blkfront.c > +++ b/drivers/block/xen-blkfront.c > @@ -1350,8 +1350,10 @@ static void blkif_free(struct blkfront_info *info, int suspend) > if (info->rq) > blk_mq_stop_hw_queues(info->rq); > > - for (i = 0; i < info->nr_rings; i++) > - blkif_free_ring(&info->rinfo[i]); > + if (info->rinfo) { > + for (i = 0; i < info->nr_rings; i++) > + blkif_free_ring(&info->rinfo[i]); > + } I'd drop this change. > > kfree(info->rinfo); > info->rinfo = NULL; > @@ -1919,6 +1921,7 @@ static int negotiate_mq(struct blkfront_info *info) > GFP_KERNEL); > if (!info->rinfo) { > xenbus_dev_fatal(info->xbdev, -ENOMEM, "allocating ring_info structure"); > + info->nr_rings = 0; > return -ENOMEM; > } Juergen
On Mon, Oct 29, 2018 at 11:31:56AM -0700, Manjunath Patil wrote: > info->nr_rings isn't adjusted in case of ENOMEM error from > negotiate_mq(). This leads to kernel panic in error path. > > Typical call stack involving panic - > #8 page_fault at ffffffff8175936f > [exception RIP: blkif_free_ring+33] > RIP: ffffffffa0149491 RSP: ffff8804f7673c08 RFLAGS: 00010292 > ... > #9 blkif_free at ffffffffa0149aaa [xen_blkfront] > #10 talk_to_blkback at ffffffffa014c8cd [xen_blkfront] > #11 blkback_changed at ffffffffa014ea8b [xen_blkfront] > #12 xenbus_otherend_changed at ffffffff81424670 > #13 backend_changed at ffffffff81426dc3 > #14 xenwatch_thread at ffffffff81422f29 > #15 kthread at ffffffff810abe6a > #16 ret_from_fork at ffffffff81754078 > > Though either of my changes avoid the panic, I included both the > changes. This issue got introduced with "7ed8ce1 xen-blkfront: move > negotiate_mq to cover all cases of new VBDs" > > Signed-off-by: Manjunath Patil <manjunath.b.patil@oracle.com> > --- > drivers/block/xen-blkfront.c | 7 +++++-- > 1 files changed, 5 insertions(+), 2 deletions(-) > > diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c > index 429d201..dc8fe25 100644 > --- a/drivers/block/xen-blkfront.c > +++ b/drivers/block/xen-blkfront.c > @@ -1350,8 +1350,10 @@ static void blkif_free(struct blkfront_info *info, int suspend) > if (info->rq) > blk_mq_stop_hw_queues(info->rq); > > - for (i = 0; i < info->nr_rings; i++) > - blkif_free_ring(&info->rinfo[i]); > + if (info->rinfo) { > + for (i = 0; i < info->nr_rings; i++) > + blkif_free_ring(&info->rinfo[i]); > + } I don't see the point in the if case here, you already fixed it by setting the nr_rings value which I think it's the correct way of fixing it. Thanks, Roger.
Thank you Juergen for your comments. I will soon send v2 patch. -Thanks, Manjunath On 10/30/2018 12:04 AM, Juergen Gross wrote: > On 29/10/2018 19:31, Manjunath Patil wrote: >> info->nr_rings isn't adjusted in case of ENOMEM error from >> negotiate_mq(). This leads to kernel panic in error path. >> >> Typical call stack involving panic - >> #8 page_fault at ffffffff8175936f >> [exception RIP: blkif_free_ring+33] >> RIP: ffffffffa0149491 RSP: ffff8804f7673c08 RFLAGS: 00010292 >> ... >> #9 blkif_free at ffffffffa0149aaa [xen_blkfront] >> #10 talk_to_blkback at ffffffffa014c8cd [xen_blkfront] >> #11 blkback_changed at ffffffffa014ea8b [xen_blkfront] >> #12 xenbus_otherend_changed at ffffffff81424670 >> #13 backend_changed at ffffffff81426dc3 >> #14 xenwatch_thread at ffffffff81422f29 >> #15 kthread at ffffffff810abe6a >> #16 ret_from_fork at ffffffff81754078 >> >> Though either of my changes avoid the panic, I included both the >> changes. This issue got introduced with "7ed8ce1 xen-blkfront: move >> negotiate_mq to cover all cases of new VBDs" > Please us the correct format for specifying another commit. > >> Signed-off-by: Manjunath Patil <manjunath.b.patil@oracle.com> > Can you please add a "Fixes:" tag and "Cc: stable@vger.kernel.org" ? > >> --- >> drivers/block/xen-blkfront.c | 7 +++++-- >> 1 files changed, 5 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c >> index 429d201..dc8fe25 100644 >> --- a/drivers/block/xen-blkfront.c >> +++ b/drivers/block/xen-blkfront.c >> @@ -1350,8 +1350,10 @@ static void blkif_free(struct blkfront_info *info, int suspend) >> if (info->rq) >> blk_mq_stop_hw_queues(info->rq); >> >> - for (i = 0; i < info->nr_rings; i++) >> - blkif_free_ring(&info->rinfo[i]); >> + if (info->rinfo) { >> + for (i = 0; i < info->nr_rings; i++) >> + blkif_free_ring(&info->rinfo[i]); >> + } > I'd drop this change. > >> >> kfree(info->rinfo); >> info->rinfo = NULL; >> @@ -1919,6 +1921,7 @@ static int negotiate_mq(struct blkfront_info *info) >> GFP_KERNEL); >> if (!info->rinfo) { >> xenbus_dev_fatal(info->xbdev, -ENOMEM, "allocating ring_info structure"); >> + info->nr_rings = 0; >> return -ENOMEM; >> } > > Juergen >
On 10/30/2018 3:39 AM, Roger Pau Monné wrote: > On Mon, Oct 29, 2018 at 11:31:56AM -0700, Manjunath Patil wrote: >> info->nr_rings isn't adjusted in case of ENOMEM error from >> negotiate_mq(). This leads to kernel panic in error path. >> >> Typical call stack involving panic - >> #8 page_fault at ffffffff8175936f >> [exception RIP: blkif_free_ring+33] >> RIP: ffffffffa0149491 RSP: ffff8804f7673c08 RFLAGS: 00010292 >> ... >> #9 blkif_free at ffffffffa0149aaa [xen_blkfront] >> #10 talk_to_blkback at ffffffffa014c8cd [xen_blkfront] >> #11 blkback_changed at ffffffffa014ea8b [xen_blkfront] >> #12 xenbus_otherend_changed at ffffffff81424670 >> #13 backend_changed at ffffffff81426dc3 >> #14 xenwatch_thread at ffffffff81422f29 >> #15 kthread at ffffffff810abe6a >> #16 ret_from_fork at ffffffff81754078 >> >> Though either of my changes avoid the panic, I included both the >> changes. This issue got introduced with "7ed8ce1 xen-blkfront: move >> negotiate_mq to cover all cases of new VBDs" >> >> Signed-off-by: Manjunath Patil <manjunath.b.patil@oracle.com> >> --- >> drivers/block/xen-blkfront.c | 7 +++++-- >> 1 files changed, 5 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c >> index 429d201..dc8fe25 100644 >> --- a/drivers/block/xen-blkfront.c >> +++ b/drivers/block/xen-blkfront.c >> @@ -1350,8 +1350,10 @@ static void blkif_free(struct blkfront_info *info, int suspend) >> if (info->rq) >> blk_mq_stop_hw_queues(info->rq); >> >> - for (i = 0; i < info->nr_rings; i++) >> - blkif_free_ring(&info->rinfo[i]); >> + if (info->rinfo) { >> + for (i = 0; i < info->nr_rings; i++) >> + blkif_free_ring(&info->rinfo[i]); >> + } > I don't see the point in the if case here, you already fixed it by > setting the nr_rings value which I think it's the correct way of > fixing it. > > Thanks, Roger. Thank you Roger for your comments. I will exclude this change and send for review again. -Thanks, Manjunath
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index 429d201..dc8fe25 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -1350,8 +1350,10 @@ static void blkif_free(struct blkfront_info *info, int suspend) if (info->rq) blk_mq_stop_hw_queues(info->rq); - for (i = 0; i < info->nr_rings; i++) - blkif_free_ring(&info->rinfo[i]); + if (info->rinfo) { + for (i = 0; i < info->nr_rings; i++) + blkif_free_ring(&info->rinfo[i]); + } kfree(info->rinfo); info->rinfo = NULL; @@ -1919,6 +1921,7 @@ static int negotiate_mq(struct blkfront_info *info) GFP_KERNEL); if (!info->rinfo) { xenbus_dev_fatal(info->xbdev, -ENOMEM, "allocating ring_info structure"); + info->nr_rings = 0; return -ENOMEM; }
info->nr_rings isn't adjusted in case of ENOMEM error from negotiate_mq(). This leads to kernel panic in error path. Typical call stack involving panic - #8 page_fault at ffffffff8175936f [exception RIP: blkif_free_ring+33] RIP: ffffffffa0149491 RSP: ffff8804f7673c08 RFLAGS: 00010292 ... #9 blkif_free at ffffffffa0149aaa [xen_blkfront] #10 talk_to_blkback at ffffffffa014c8cd [xen_blkfront] #11 blkback_changed at ffffffffa014ea8b [xen_blkfront] #12 xenbus_otherend_changed at ffffffff81424670 #13 backend_changed at ffffffff81426dc3 #14 xenwatch_thread at ffffffff81422f29 #15 kthread at ffffffff810abe6a #16 ret_from_fork at ffffffff81754078 Though either of my changes avoid the panic, I included both the changes. This issue got introduced with "7ed8ce1 xen-blkfront: move negotiate_mq to cover all cases of new VBDs" Signed-off-by: Manjunath Patil <manjunath.b.patil@oracle.com> --- drivers/block/xen-blkfront.c | 7 +++++-- 1 files changed, 5 insertions(+), 2 deletions(-)