On 2/8/21 8:21 PM, Ming Lei wrote:
On Mon, Feb 08, 2021 at 10:42:28AM -0800, Sagi Grimberg wrote:
Hi Sagi
On 2/8/21 5:46 PM, Sagi Grimberg wrote:
Hello
We found this kernel NULL pointer issue with latest
linux-block/for-next and it's 100% reproduced, let me know
if you need more info/testing, thanks
Kernel repo:
https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git
Commit: 11f8b6fd0db9 - Merge branch 'for-5.12/io_uring' into for-next
Reproducer: blktests nvme-tcp/012
Thanks for reporting Ming, I've tried to reproduce this on my VM
but did not succeed. Given that you have it 100% reproducible,
can you try to revert commit:
0dc9edaf80ea nvme-tcp: pass multipage bvec to request iov_iter
Revert this commit fixed the issue and I've attached the config. :)
Good to know,
I see some differences that I should probably change to hit this:
--
@@ -254,14 +256,15 @@ CONFIG_PERF_EVENTS=y
# end of Kernel Performance Events And Counters
CONFIG_VM_EVENT_COUNTERS=y
+CONFIG_SLUB_DEBUG=y
# CONFIG_COMPAT_BRK is not set
-CONFIG_SLAB=y
-# CONFIG_SLUB is not set
-# CONFIG_SLOB is not set
-CONFIG_SLAB_MERGE_DEFAULT=y
-# CONFIG_SLAB_FREELIST_RANDOM is not set
+# CONFIG_SLAB is not set
+CONFIG_SLUB=y
+# CONFIG_SLAB_MERGE_DEFAULT is not set
+CONFIG_SLAB_FREELIST_RANDOM=y
# CONFIG_SLAB_FREELIST_HARDENED is not set
-# CONFIG_SHUFFLE_PAGE_ALLOCATOR is not set
+CONFIG_SHUFFLE_PAGE_ALLOCATOR=y
+CONFIG_SLUB_CPU_PARTIAL=y
CONFIG_SYSTEM_DATA_VERIFICATION=y
CONFIG_PROFILING=y
CONFIG_TRACEPOINTS=y
@@ -299,7 +302,8 @@ CONFIG_HAVE_INTEL_TXT=y
CONFIG_X86_64_SMP=y
CONFIG_ARCH_SUPPORTS_UPROBES=y
CONFIG_FIX_EARLYCON_MEM=y
-CONFIG_PGTABLE_LEVELS=4
+CONFIG_DYNAMIC_PHYSICAL_MASK=y
+CONFIG_PGTABLE_LEVELS=5
CONFIG_CC_HAS_SANE_STACKPROTECTOR=y
--
Probably CONFIG_SLUB and CONFIG_SLUB_DEBUG should be used.
Used your profile and this still does not happen :(
One obvious error is that nr_segments is computed wrong.
Yi, can you try the following patch?
diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
index 881d28eb15e9..a393d99b74e1 100644
--- a/drivers/nvme/host/tcp.c
+++ b/drivers/nvme/host/tcp.c
@@ -239,9 +239,14 @@ static void nvme_tcp_init_iter(struct nvme_tcp_request *req,
offset = 0;
} else {
struct bio *bio = req->curr_bio;
+ struct bio_vec bv;
+ struct bvec_iter iter;
+
+ nsegs = 0;
+ bio_for_each_bvec(bv, bio, iter)
+ nsegs++;
vec = __bvec_iter_bvec(bio->bi_io_vec, bio->bi_iter);
- nsegs = bio_segments(bio);
This was exactly the patch that caused the issue.
