<feed xmlns='http://www.w3.org/2005/Atom'>
<title>kernel/linux.git/drivers/infiniband, branch v5.10.258</title>
<subtitle>Linux kernel stable tree (mirror)</subtitle>
<id>https://git.radix-linux.su/kernel/linux.git/atom?h=v5.10.258</id>
<link rel='self' href='https://git.radix-linux.su/kernel/linux.git/atom?h=v5.10.258'/>
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<updated>2026-06-01T15:29:52+00:00</updated>
<entry>
<title>RDMA/siw: Reject MPA FPDU length underflow before signed receive math</title>
<updated>2026-06-01T15:29:52+00:00</updated>
<author>
<name>Michael Bommarito</name>
<email>michael.bommarito@gmail.com</email>
</author>
<published>2026-05-13T17:53:24+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=683f7cfbf514193d63c0efa079f3352bde84c2e0'/>
<id>urn:sha1:683f7cfbf514193d63c0efa079f3352bde84c2e0</id>
<content type='text'>
commit 0ce1bc9e46ecabe84772bb561e373c0d9876d6f2 upstream.

A malicious connected siw peer can send an iWARP FPDU whose MPA length
field (c_hdr-&gt;mpa_len, 16 bit big-endian, peer-controlled) is smaller
than the fixed DDP/RDMAP header for the announced opcode. Soft-iWARP
parses the full header in siw_get_hdr() based on iwarp_pktinfo[opcode]
.hdr_len, but never compares mpa_len against that header length.

siw_tcp_rx_data() then derives

    srx-&gt;fpdu_part_rem = be16_to_cpu(mpa_len) - fpdu_part_rcvd
                         + MPA_HDR_SIZE;

where fpdu_part_rcvd equals iwarp_pktinfo[opcode].hdr_len at this
point. For a tagged WRITE (hdr_len 16, MPA_HDR_SIZE 2) the smallest
on-wire mpa_len of 0 yields fpdu_part_rem = -14, and any mpa_len below
hdr_len - MPA_HDR_SIZE underflows to a negative int.

The signed value then flows into siw_proc_write()/siw_proc_rresp() as

    bytes = min(srx-&gt;fpdu_part_rem, srx-&gt;skb_new);

is handed to siw_check_mem() as an int len (whose interval check
addr + len &gt; mem-&gt;va + mem-&gt;len is satisfied for a valid base when
len is negative), and reaches siw_rx_data() -&gt; siw_rx_kva() /
siw_rx_umem() -&gt; skb_copy_bits() as a signed copy length. The header
copy branch in skb_copy_bits() promotes that to size_t, producing a
multi-gigabyte read.

KASAN under a KUnit harness that drives the real kernel TCP receive
path -- a loopback AF_INET socketpair, the malformed FPDU written via
kernel_sendmsg, sk_data_ready firing in softirq, tcp_read_sock
dispatching to siw_tcp_rx_data -- reports:

    BUG: KASAN: use-after-free in skb_copy_bits+0x284/0x480
    Read of size 4294967295 at addr ffff888...
    Call Trace:
     skb_copy_bits
     siw_rx_kva
     siw_rx_data
     siw_check_mem
     siw_proc_write
     siw_tcp_rx_data
     __tcp_read_sock
     siw_qp_llp_data_ready
     tcp_data_ready
     tcp_data_queue

Add the missing invariant at the earliest point where the peer header
is fully assembled. iwarp_pktinfo[*].hdr_len - MPA_HDR_SIZE is exactly
the value the siw transmitter uses as the minimum mpa_len for each
opcode (drivers/infiniband/sw/siw/siw_qp.c:33), so this matches the
protocol contract. Out-of-range FPDUs terminate the connection with
TERM_ERROR_LAYER_LLP / LLP_ETYPE_MPA / LLP_ECODE_FPDU_START -- which
is RFC 5044 Section 8 error code 3 ("Marker and ULPDU Length fields
do not agree on the start of an FPDU"), the correct framing-error
class for this inconsistency.

Fixes: 8b6a361b8c48 ("rdma/siw: receive path")
Link: https://patch.msgid.link/r/20260513175325.2042630-2-michael.bommarito@gmail.com
Cc: stable@vger.kernel.org
Signed-off-by: Michael Bommarito &lt;michael.bommarito@gmail.com&gt;
Assisted-by: Claude:claude-opus-4-7
Acked-by: Bernard Metzler &lt;bernard.metzler@linux.dev&gt;
Signed-off-by: Jason Gunthorpe &lt;jgg@nvidia.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>RDMA/core: Prefer NLA_NUL_STRING</title>
<updated>2026-06-01T15:29:37+00:00</updated>
<author>
<name>Florian Westphal</name>
<email>fw@strlen.de</email>
</author>
<published>2026-03-30T12:27:39+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=fcd07d3b8ee7a39b344d73aed69c1a68cd9eacdf'/>
<id>urn:sha1:fcd07d3b8ee7a39b344d73aed69c1a68cd9eacdf</id>
<content type='text'>
[ Upstream commit 6ed3d14fc45d3da6025e7fe4a6a09066856698e2 ]

These attributes are evaluated as c-string (passed to strcmp), but
NLA_STRING doesn't check for the presence of a \0 terminator.

Either this needs to switch to nla_strcmp() and needs to adjust printf fmt
specifier to not use plain %s, or this needs to use NLA_NUL_STRING.

As the code has been this way for long time, it seems to me that userspace
does include the terminating nul, even tough its not enforced so far, and
thus NLA_NUL_STRING use is the simpler solution.

Fixes: 30dc5e63d6a5 ("RDMA/core: Add support for iWARP Port Mapper user space service")
Link: https://patch.msgid.link/r/20260330122742.13315-1-fw@strlen.de
Signed-off-by: Florian Westphal &lt;fw@strlen.de&gt;
Signed-off-by: Jason Gunthorpe &lt;jgg@nvidia.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>RDMA/vmw_pvrdma: Fix double free on pvrdma_alloc_ucontext() error path</title>
<updated>2026-06-01T15:29:27+00:00</updated>
<author>
<name>Jason Gunthorpe</name>
<email>jgg@nvidia.com</email>
</author>
<published>2026-04-28T16:17:43+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=269967d7693304e1f06ed2dff4ebbbeeb397cda4'/>
<id>urn:sha1:269967d7693304e1f06ed2dff4ebbbeeb397cda4</id>
<content type='text'>
commit e38e86995df27f1f854063dab1f0c6a513db3faf upstream.

Sashiko points out that pvrdma_uar_free() is already called within
pvrdma_dealloc_ucontext(), so calling it before triggers a double free.

Cc: stable@vger.kernel.org
Fixes: 29c8d9eba550 ("IB: Add vmw_pvrdma driver")
Link: https://sashiko.dev/#/patchset/0-v1-e911b76a94d1%2B65d95-rdma_udata_rep_jgg%40nvidia.com?part=4
Link: https://patch.msgid.link/r/10-v1-41f3135e5565+9d2-rdma_ai_fixes1_jgg@nvidia.com
Signed-off-by: Jason Gunthorpe &lt;jgg@nvidia.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>RDMA/rxe: Reject unknown opcodes before ICRC processing</title>
<updated>2026-06-01T15:29:27+00:00</updated>
<author>
<name>Michael Bommarito</name>
<email>michael.bommarito@gmail.com</email>
</author>
<published>2026-04-14T11:15:55+00:00</published>
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<id>urn:sha1:318787fa7193bd79691f2ebce4e80cb6abd0faef</id>
<content type='text'>
commit 4c6f86d85d03cdb33addce86aa69aa795ca6c47a upstream.

Even after applying commit 7244491dab34 ("RDMA/rxe: Validate pad and ICRC
before payload_size() in rxe_rcv"), a single unauthenticated UDP packet
can still trigger panic.  That patch handled payload_size() underflow only
for valid opcodes with short packets, not for packets carrying an unknown
opcode.  The unknown-opcode OOB read described below predates that commit
and reaches back to the initial Soft RoCE driver.

The check added there reads

    pkt-&gt;paylen &lt; header_size(pkt) + bth_pad(pkt) + RXE_ICRC_SIZE

where header_size(pkt) expands to rxe_opcode[pkt-&gt;opcode].length.  The
rxe_opcode[] array has 256 entries but is only populated for defined IB
opcodes; any other entry (for example opcode 0xff) is zero-initialized, so
length == 0 and the check degenerates to

    pkt-&gt;paylen &lt; 0 + bth_pad(pkt) + RXE_ICRC_SIZE

which does not constrain pkt-&gt;paylen enough.  rxe_icrc_hdr() then computes

    rxe_opcode[pkt-&gt;opcode].length - RXE_BTH_BYTES

which underflows when length == 0 and passes a huge value to rxe_crc32(),
causing an out-of-bounds read of the skb payload.

Reproduced on v7.0-rc7 with that fix applied, QEMU/KVM with
CONFIG_RDMA_RXE=y and CONFIG_KASAN=y, after

    rdma link add rxe0 type rxe netdev eth0

A single 48-byte UDP packet to port 4791 with BTH opcode=0xff and
QPN=IB_MULTICAST_QPN triggers:

    BUG: KASAN: slab-out-of-bounds in crc32_le+0x115/0x170
    Read of size 1 at addr ...
    The buggy address is located 0 bytes to the right of
     allocated 704-byte region
    Call Trace:
     crc32_le+0x115/0x170
     rxe_icrc_hdr.isra.0+0x226/0x300
     rxe_icrc_check+0x13f/0x3a0
     rxe_rcv+0x6e1/0x16e0
     rxe_udp_encap_recv+0x20a/0x320
     udp_queue_rcv_one_skb+0x7ed/0x12c0

Subsequent packets with the same shape fault on unmapped memory and panic
the kernel.  The trigger requires only module load and "rdma link add"; no
QP, no connection, and no authentication.

Fix this by rejecting packets whose opcode has no rxe_opcode[] entry,
detected via the zero mask or zero length, before any length arithmetic
runs.

Cc: stable@vger.kernel.org
Fixes: 8700e3e7c485 ("Soft RoCE driver")
Link: https://patch.msgid.link/r/20260414111555.3386793-1-michael.bommarito@gmail.com
Assisted-by: Claude:claude-opus-4-6
Signed-off-by: Michael Bommarito &lt;michael.bommarito@gmail.com&gt;
Reviewed-by: Zhu Yanjun &lt;yanjun.zhu@linux.dev&gt;
Signed-off-by: Jason Gunthorpe &lt;jgg@nvidia.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>RDMA/ocrdma: Don't NULL deref uctx on errors in ocrdma_copy_pd_uresp()</title>
<updated>2026-06-01T15:29:26+00:00</updated>
<author>
<name>Jason Gunthorpe</name>
<email>jgg@nvidia.com</email>
</author>
<published>2026-04-28T16:17:42+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=b610f33c5523fe26f6dd897667fff9c7a1de5905'/>
<id>urn:sha1:b610f33c5523fe26f6dd897667fff9c7a1de5905</id>
<content type='text'>
commit 34fbf48cf3b410d2a6e8c586fa952a36331ca5ba upstream.

Sashiko points out that pd-&gt;uctx isn't initialized until late in the
function so all these error flow references are NULL and will crash. Use
the uctx that isn't NULL.

Cc: stable@vger.kernel.org
Fixes: fe2caefcdf58 ("RDMA/ocrdma: Add driver for Emulex OneConnect IBoE RDMA adapter")
Link: https://sashiko.dev/#/patchset/0-v1-e911b76a94d1%2B65d95-rdma_udata_rep_jgg%40nvidia.com?part=4
Link: https://patch.msgid.link/r/9-v1-41f3135e5565+9d2-rdma_ai_fixes1_jgg@nvidia.com
Signed-off-by: Jason Gunthorpe &lt;jgg@nvidia.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>RDMA/mlx4: Fix resource leak on error in mlx4_ib_create_srq()</title>
<updated>2026-06-01T15:29:26+00:00</updated>
<author>
<name>Jason Gunthorpe</name>
<email>jgg@nvidia.com</email>
</author>
<published>2026-04-28T16:17:44+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=53fd4c03558672ccb167754fbacbf045c7ab335c'/>
<id>urn:sha1:53fd4c03558672ccb167754fbacbf045c7ab335c</id>
<content type='text'>
commit c54c7e4cb679c0aaa1cb489b9c3f2cd98e63a44c upstream.

Sashiko points out that mlx4_srq_alloc() was not undone during error
unwind, add the missing call to mlx4_srq_free().

Cc: stable@vger.kernel.org
Fixes: 225c7b1feef1 ("IB/mlx4: Add a driver Mellanox ConnectX InfiniBand adapters")
Link: https://sashiko.dev/#/patchset/0-v1-e911b76a94d1%2B65d95-rdma_udata_rep_jgg%40nvidia.com?part=8
Link: https://patch.msgid.link/r/11-v1-41f3135e5565+9d2-rdma_ai_fixes1_jgg@nvidia.com
Signed-off-by: Jason Gunthorpe &lt;jgg@nvidia.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>IB/core: Fix zero dmac race in neighbor resolution</title>
<updated>2026-06-01T15:29:21+00:00</updated>
<author>
<name>Chen Zhao</name>
<email>chezhao@nvidia.com</email>
</author>
<published>2026-04-05T15:44:55+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=31b7b1d2e04ad8e54b6c97831791697a6cc47501'/>
<id>urn:sha1:31b7b1d2e04ad8e54b6c97831791697a6cc47501</id>
<content type='text'>
commit 5e6de34d82b49cab9d8a42063e9cd0f22a4f31e5 upstream.

dst_fetch_ha() checks nud_state without holding the neighbor lock, then
copies ha under the seqlock. A race in __neigh_update() where nud_state
is set to NUD_REACHABLE before ha is written allows dst_fetch_ha() to
read a zero MAC address while the seqlock reports no concurrent writer.

netevent_callback amplifies this by waking ALL pending addr_req workers
when ANY neighbor becomes NUD_VALID. At scale (N peers resolving ARP
concurrently), the hit probability scales as N^2, making it near-certain
for large RDMA workloads.

N(A): neigh_update(A)                   W(A): addr_resolve(A)
 |                                       [sleep]
 | write_lock_bh(&amp;A-&gt;lock)               |
 | A-&gt;nud_state = NUD_REACHABLE          |
 | // A-&gt;ha is still 0                   |
 |                                       [woken by netevent_cb() of
 |                                         another neighbour]
 |                                       | dst_fetch_ha(A)
 |                                       |   A-&gt;nud_state &amp; NUD_VALID
 |                                       |   read_seqbegin(&amp;A-&gt;ha_lock)
 |                                       |   snapshot = A-&gt;ha  /* 0 */
 |                                       |   read_seqretry(&amp;A-&gt;ha_lock)
 |                                       |   return snapshot
 | seqlock(&amp;A-&gt;ha_lock)
 | A-&gt;ha = mac_A     /* too late */
 | sequnlock(&amp;A-&gt;ha_lock)
 | write_unlock_bh(&amp;A-&gt;lock)

The incorrect/zero mac is read and programmed in the device QP while it
was not yet updated. This causes silent packet loss and eventual
RETRY_EXC_ERR.

Fix by holding the neighbor read lock across the nud_state check and
ha copy in dst_fetch_ha(), ensuring it synchronizes with
__neigh_update() which is updating while holding the write lock.

Cc: stable@vger.kernel.org
Fixes: 92ebb6a0a13a ("IB/cm: Remove now useless rcu_lock in dst_fetch_ha")
Link: https://patch.msgid.link/r/20260405-fix-dmac-race-v1-1-cfa1ec2ce54a@nvidia.com
Signed-off-by: Chen Zhao &lt;chezhao@nvidia.com&gt;
Reviewed-by: Parav Pandit &lt;parav@nvidia.com&gt;
Signed-off-by: Leon Romanovsky &lt;leonro@nvidia.com&gt;
Signed-off-by: Jason Gunthorpe &lt;jgg@nvidia.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>RDMA/rxe: Validate pad and ICRC before payload_size() in rxe_rcv</title>
<updated>2026-06-01T15:29:19+00:00</updated>
<author>
<name>hkbinbin</name>
<email>hkbinbinbin@gmail.com</email>
</author>
<published>2026-04-01T12:19:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=c4376c672c3648d5bdc31dfffc329d07164f93c4'/>
<id>urn:sha1:c4376c672c3648d5bdc31dfffc329d07164f93c4</id>
<content type='text'>
commit 7244491dab347f648e661da96dc0febadd9daec3 upstream.

rxe_rcv() currently checks only that the incoming packet is at least
header_size(pkt) bytes long before payload_size() is used.

However, payload_size() subtracts both the attacker-controlled BTH pad
field and RXE_ICRC_SIZE from pkt-&gt;paylen:

  payload_size = pkt-&gt;paylen - offset[RXE_PAYLOAD] - bth_pad(pkt)
                 - RXE_ICRC_SIZE

This means a short packet can still make payload_size() underflow even
if it includes enough bytes for the fixed headers. Simply requiring
header_size(pkt) + RXE_ICRC_SIZE is not sufficient either, because a
packet with a forged non-zero BTH pad can still leave payload_size()
negative and pass an underflowed value to later receive-path users.

Fix this by validating pkt-&gt;paylen against the full minimum length
required by payload_size(): header_size(pkt) + bth_pad(pkt) +
RXE_ICRC_SIZE.

Cc: stable@vger.kernel.org
Fixes: 8700e3e7c485 ("Soft RoCE driver")
Link: https://patch.msgid.link/r/20260401121907.1468366-1-hkbinbinbin@gmail.com
Signed-off-by: hkbinbin &lt;hkbinbinbin@gmail.com&gt;
Reviewed-by: Zhu Yanjun &lt;yanjun.zhu@linux.dev&gt;
Signed-off-by: Jason Gunthorpe &lt;jgg@nvidia.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>IB/mad: Don't call to function that might sleep while in atomic context</title>
<updated>2026-06-01T15:29:14+00:00</updated>
<author>
<name>Leonid Ravich</name>
<email>lravich@gmail.com</email>
</author>
<published>2026-04-21T13:28:08+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=d45e6ccb8e98d8339631f32984d345a663e74ce2'/>
<id>urn:sha1:d45e6ccb8e98d8339631f32984d345a663e74ce2</id>
<content type='text'>
commit 5c20311d76cbaeb7ed2ecf9c8b8322f8fc4a7ae3 upstream.

Tracepoints are not allowed to sleep, as such the following splat is
generated due to call to ib_query_pkey() in atomic context.

WARNING: CPU: 0 PID: 1888000 at kernel/trace/ring_buffer.c:2492 rb_commit+0xc1/0x220
CPU: 0 PID: 1888000 Comm: kworker/u9:0 Kdump: loaded Tainted: G           OE    --------- -  - 4.18.0-305.3.1.el8.x86_64 #1
 Hardware name: Red Hat KVM, BIOS 1.13.0-2.module_el8.3.0+555+a55c8938 04/01/2014
 Workqueue: ib-comp-unb-wq ib_cq_poll_work [ib_core]
 RIP: 0010:rb_commit+0xc1/0x220
 RSP: 0000:ffffa8ac80f9bca0 EFLAGS: 00010202
 RAX: ffff8951c7c01300 RBX: ffff8951c7c14a00 RCX: 0000000000000246
 RDX: ffff8951c707c000 RSI: ffff8951c707c57c RDI: ffff8951c7c14a00
 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
 R10: ffff8951c7c01300 R11: 0000000000000001 R12: 0000000000000246
 R13: 0000000000000000 R14: ffffffff964c70c0 R15: 0000000000000000
 FS:  0000000000000000(0000) GS:ffff8951fbc00000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 00007f20e8f39010 CR3: 000000002ca10005 CR4: 0000000000170ef0
 Call Trace:
  ring_buffer_unlock_commit+0x1d/0xa0
  trace_buffer_unlock_commit_regs+0x3b/0x1b0
  trace_event_buffer_commit+0x67/0x1d0
  trace_event_raw_event_ib_mad_recv_done_handler+0x11c/0x160 [ib_core]
  ib_mad_recv_done+0x48b/0xc10 [ib_core]
  ? trace_event_raw_event_cq_poll+0x6f/0xb0 [ib_core]
  __ib_process_cq+0x91/0x1c0 [ib_core]
  ib_cq_poll_work+0x26/0x80 [ib_core]
  process_one_work+0x1a7/0x360
  ? create_worker+0x1a0/0x1a0
  worker_thread+0x30/0x390
  ? create_worker+0x1a0/0x1a0
  kthread+0x116/0x130
  ? kthread_flush_work_fn+0x10/0x10
  ret_from_fork+0x35/0x40
 ---[ end trace 78ba8509d3830a16 ]---

Fixes: 821bf1de45a1 ("IB/MAD: Add recv path trace point")
Signed-off-by: Leonid Ravich &lt;lravich@gmail.com&gt;
Link: https://lore.kernel.org/r/Y2t5feomyznrVj7V@leonid-Inspiron-3421
Signed-off-by: Leon Romanovsky &lt;leon@kernel.org&gt;
[ kovalev: bp to fix CVE-2022-50472 ]
Signed-off-by: Vasiliy Kovalev &lt;kovalev@altlinux.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>RDMA/rw: Fall back to direct SGE on MR pool exhaustion</title>
<updated>2026-04-18T08:31:06+00:00</updated>
<author>
<name>Chuck Lever</name>
<email>chuck.lever@oracle.com</email>
</author>
<published>2026-03-13T19:41:58+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=8a8f4051bea098b44c0afdf7234dfb1121a9cb32'/>
<id>urn:sha1:8a8f4051bea098b44c0afdf7234dfb1121a9cb32</id>
<content type='text'>
[ Upstream commit 00da250c21b074ea9494c375d0117b69e5b1d0a4 ]

When IOMMU passthrough mode is active, ib_dma_map_sgtable_attrs()
produces no coalescing: each scatterlist page maps 1:1 to a DMA
entry, so sgt.nents equals the raw page count. A 1 MB transfer
yields 256 DMA entries. If that count exceeds the device's
max_sgl_rd threshold (an optimization hint from mlx5 firmware),
rdma_rw_io_needs_mr() steers the operation into the MR
registration path. Each such operation consumes one or more MRs
from a pool sized at max_rdma_ctxs -- roughly one MR per
concurrent context. Under write-intensive workloads that issue
many concurrent RDMA READs, the pool is rapidly exhausted,
ib_mr_pool_get() returns NULL, and rdma_rw_init_one_mr() returns
-EAGAIN. Upper layer protocols treat this as a fatal DMA mapping
failure and tear down the connection.

The max_sgl_rd check is a performance optimization, not a
correctness requirement: the device can handle large SGE counts
via direct posting, just less efficiently than with MR
registration. When the MR pool cannot satisfy a request, falling
back to the direct SGE (map_wrs) path avoids the connection
reset while preserving the MR optimization for the common case
where pool resources are available.

Add a fallback in rdma_rw_ctx_init() so that -EAGAIN from
rdma_rw_init_mr_wrs() triggers direct SGE posting instead of
propagating the error. iWARP devices, which mandate MR
registration for RDMA READs, and force_mr debug mode continue
to treat -EAGAIN as terminal.

Fixes: 00bd1439f464 ("RDMA/rw: Support threshold for registration vs scattering to local pages")
Signed-off-by: Chuck Lever &lt;chuck.lever@oracle.com&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Link: https://patch.msgid.link/20260313194201.5818-2-cel@kernel.org
Signed-off-by: Leon Romanovsky &lt;leon@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
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