--- /dev/null
+From stable+bounces-116416-greg=kroah.com@vger.kernel.org Fri Feb 14 14:19:30 2025
+From: Max Kellermann <max.kellermann@ionos.com>
+Date: Fri, 14 Feb 2025 14:12:25 +0100
+Subject: fs/netfs/read_collect: fix crash due to uninitialized `prev` variable
+To: dhowells@redhat.com, netfs@lists.linux.dev, linux-kernel@vger.kernel.org
+Cc: Max Kellermann <max.kellermann@ionos.com>, stable@vger.kernel.org
+Message-ID: <20250214131225.492756-1-max.kellermann@ionos.com>
+
+From: Max Kellermann <max.kellermann@ionos.com>
+
+[ Just like the other two netfs patches I sent yesterday, this one
+ doesn't apply to v6.14 as it was obsoleted by commit e2d46f2ec332
+ ("netfs: Change the read result collector to only use one work item"). ]
+
+When checking whether the edges of adjacent subrequests touch, the
+`prev` variable is deferenced, but it might not have been initialized.
+This causes crashes like this one:
+
+ BUG: unable to handle page fault for address: 0000000181343843
+ #PF: supervisor read access in kernel mode
+ #PF: error_code(0x0000) - not-present page
+ PGD 8000001c66db0067 P4D 8000001c66db0067 PUD 0
+ Oops: Oops: 0000 [#1] SMP PTI
+ CPU: 1 UID: 33333 PID: 24424 Comm: php-cgi8.2 Kdump: loaded Not tainted 6.13.2-cm4all0-hp+ #427
+ Hardware name: HP ProLiant DL380 Gen9/ProLiant DL380 Gen9, BIOS P89 11/23/2021
+ RIP: 0010:netfs_consume_read_data.isra.0+0x5ef/0xb00
+ Code: fe ff ff 48 8b 83 88 00 00 00 48 8b 4c 24 30 4c 8b 43 78 48 85 c0 48 8d 51 70 75 20 48 8b 73 30 48 39 d6 74 17 48 8b 7c 24 40 <48> 8b 4f 78 48 03 4f 68 48 39 4b 68 0f 84 ab 02 00 00 49 29 c0 48
+ RSP: 0000:ffffc90037adbd00 EFLAGS: 00010283
+ RAX: 0000000000000000 RBX: ffff88811bda0600 RCX: ffff888620e7b980
+ RDX: ffff888620e7b9f0 RSI: ffff88811bda0428 RDI: 00000001813437cb
+ RBP: 0000000000000000 R08: 0000000000004000 R09: 0000000000000000
+ R10: ffffffff82e070c0 R11: 0000000007ffffff R12: 0000000000004000
+ R13: ffff888620e7bb68 R14: 0000000000008000 R15: ffff888620e7bb68
+ FS: 00007ff2e0e7ddc0(0000) GS:ffff88981f840000(0000) knlGS:0000000000000000
+ CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
+ CR2: 0000000181343843 CR3: 0000001bc10ba006 CR4: 00000000001706f0
+ Call Trace:
+ <TASK>
+ ? __die+0x1f/0x60
+ ? page_fault_oops+0x15c/0x450
+ ? search_extable+0x22/0x30
+ ? netfs_consume_read_data.isra.0+0x5ef/0xb00
+ ? search_module_extables+0xe/0x40
+ ? exc_page_fault+0x5e/0x100
+ ? asm_exc_page_fault+0x22/0x30
+ ? netfs_consume_read_data.isra.0+0x5ef/0xb00
+ ? intel_iommu_unmap_pages+0xaa/0x190
+ ? __pfx_cachefiles_read_complete+0x10/0x10
+ netfs_read_subreq_terminated+0x24f/0x390
+ cachefiles_read_complete+0x48/0xf0
+ iomap_dio_bio_end_io+0x125/0x160
+ blk_update_request+0xea/0x3e0
+ scsi_end_request+0x27/0x190
+ scsi_io_completion+0x43/0x6c0
+ blk_complete_reqs+0x40/0x50
+ handle_softirqs+0xd1/0x280
+ irq_exit_rcu+0x91/0xb0
+ common_interrupt+0x3b/0xa0
+ asm_common_interrupt+0x22/0x40
+ RIP: 0033:0x55fe8470d2ab
+ Code: 00 00 3c 7e 74 3b 3c b6 0f 84 dd 03 00 00 3c 1e 74 2f 83 c1 01 48 83 c2 38 48 83 c7 30 44 39 d1 74 3e 48 63 42 08 85 c0 79 a3 <49> 8b 46 48 8b 04 38 f6 c4 04 75 0b 0f b6 42 30 83 e0 0c 3c 04 75
+ RSP: 002b:00007ffca5ef2720 EFLAGS: 00000216
+ RAX: 0000000000000023 RBX: 0000000000000008 RCX: 000000000000001b
+ RDX: 00007ff2e0cdb6f8 RSI: 0000000000000006 RDI: 0000000000000510
+ RBP: 00007ffca5ef27a0 R08: 00007ffca5ef2720 R09: 0000000000000001
+ R10: 000000000000001e R11: 00007ff2e0c10d08 R12: 0000000000000001
+ R13: 0000000000000120 R14: 00007ff2e0cb1ed0 R15: 00000000000000b0
+ </TASK>
+
+Fixes: ee4cdf7ba857 ("netfs: Speed up buffered reading")
+Cc: stable@vger.kernel.org
+Signed-off-by: Max Kellermann <max.kellermann@ionos.com>
+Signed-off-by: David Howells <dhowells@redhat.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ fs/netfs/read_collect.c | 21 +++++++++++----------
+ 1 file changed, 11 insertions(+), 10 deletions(-)
+
+--- a/fs/netfs/read_collect.c
++++ b/fs/netfs/read_collect.c
+@@ -258,17 +258,18 @@ donation_changed:
+ */
+ if (!subreq->consumed &&
+ !prev_donated &&
+- !list_is_first(&subreq->rreq_link, &rreq->subrequests) &&
+- subreq->start == prev->start + prev->len) {
++ !list_is_first(&subreq->rreq_link, &rreq->subrequests)) {
+ prev = list_prev_entry(subreq, rreq_link);
+- WRITE_ONCE(prev->next_donated, prev->next_donated + subreq->len);
+- subreq->start += subreq->len;
+- subreq->len = 0;
+- subreq->transferred = 0;
+- trace_netfs_donate(rreq, subreq, prev, subreq->len,
+- netfs_trace_donate_to_prev);
+- trace_netfs_sreq(subreq, netfs_sreq_trace_donate_to_prev);
+- goto remove_subreq_locked;
++ if (subreq->start == prev->start + prev->len) {
++ WRITE_ONCE(prev->next_donated, prev->next_donated + subreq->len);
++ subreq->start += subreq->len;
++ subreq->len = 0;
++ subreq->transferred = 0;
++ trace_netfs_donate(rreq, subreq, prev, subreq->len,
++ netfs_trace_donate_to_prev);
++ trace_netfs_sreq(subreq, netfs_sreq_trace_donate_to_prev);
++ goto remove_subreq_locked;
++ }
+ }
+
+ /* If we can't donate down the chain, donate up the chain instead. */
--- /dev/null
+From stable+bounces-114731-greg=kroah.com@vger.kernel.org Mon Feb 10 23:32:01 2025
+From: Max Kellermann <max.kellermann@ionos.com>
+Date: Mon, 10 Feb 2025 23:31:44 +0100
+Subject: fs/netfs/read_pgpriv2: skip folio queues without `marks3`
+To: dhowells@redhat.com, netfs@lists.linux.dev, linux-kernel@vger.kernel.org
+Cc: Max Kellermann <max.kellermann@ionos.com>, stable@vger.kernel.org
+Message-ID: <20250210223144.3481766-1-max.kellermann@ionos.com>
+
+From: Max Kellermann <max.kellermann@ionos.com>
+
+[ Note this patch doesn't apply to v6.14 as it was obsoleted by commit
+ e2d46f2ec332 ("netfs: Change the read result collector to only use one
+ work item"). ]
+
+At the beginning of the function, folio queues with marks3==0 are
+skipped, but after that, the `marks3` field is ignored. If one such
+queue is found, `slot` is set to 64 (because `__ffs(0)==64`), leading
+to a buffer overflow in the folioq_folio() call. The resulting crash
+may look like this:
+
+ BUG: kernel NULL pointer dereference, address: 0000000000000000
+ #PF: supervisor read access in kernel mode
+ #PF: error_code(0x0000) - not-present page
+ PGD 0 P4D 0
+ Oops: Oops: 0000 [#1] SMP PTI
+ CPU: 11 UID: 0 PID: 2909 Comm: kworker/u262:1 Not tainted 6.13.1-cm4all2-vm #415
+ Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014
+ Workqueue: events_unbound netfs_read_termination_worker
+ RIP: 0010:netfs_pgpriv2_write_to_the_cache+0x15a/0x3f0
+ Code: 48 85 c0 48 89 44 24 08 0f 84 24 01 00 00 48 8b 80 40 01 00 00 48 8b 7c 24 08 f3 48 0f bc c0 89 44 24 18 89 c0 48 8b 74 c7 08 <48> 8b 06 48 c7 04 24 00 10 00 00 a8 40 74 10 0f b6 4e 40 b8 00 10
+ RSP: 0018:ffffbbc440effe18 EFLAGS: 00010203
+ RAX: 0000000000000040 RBX: ffff96f8fc034000 RCX: 0000000000000000
+ RDX: 0000000000000040 RSI: 0000000000000000 RDI: ffff96f8fc036400
+ RBP: 0000000000001000 R08: ffff96f9132bb400 R09: 0000000000001000
+ R10: ffff96f8c1263c80 R11: 0000000000000003 R12: 0000000000001000
+ R13: ffff96f8fb75ade8 R14: fffffaaf5ca90000 R15: ffff96f8fb75ad00
+ FS: 0000000000000000(0000) GS:ffff9703cf0c0000(0000) knlGS:0000000000000000
+ CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
+ CR2: 0000000000000000 CR3: 000000010c9ca003 CR4: 00000000001706b0
+ DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
+ DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
+ Call Trace:
+ <TASK>
+ ? __die+0x1f/0x60
+ ? page_fault_oops+0x158/0x450
+ ? search_extable+0x22/0x30
+ ? netfs_pgpriv2_write_to_the_cache+0x15a/0x3f0
+ ? search_module_extables+0xe/0x40
+ ? exc_page_fault+0x62/0x120
+ ? asm_exc_page_fault+0x22/0x30
+ ? netfs_pgpriv2_write_to_the_cache+0x15a/0x3f0
+ ? netfs_pgpriv2_write_to_the_cache+0xf6/0x3f0
+ netfs_read_termination_worker+0x1f/0x60
+ process_one_work+0x138/0x2d0
+ worker_thread+0x2a5/0x3b0
+ ? __pfx_worker_thread+0x10/0x10
+ kthread+0xba/0xe0
+ ? __pfx_kthread+0x10/0x10
+ ret_from_fork+0x30/0x50
+ ? __pfx_kthread+0x10/0x10
+ ret_from_fork_asm+0x1a/0x30
+ </TASK>
+
+Fixes: ee4cdf7ba857 ("netfs: Speed up buffered reading")
+Cc: stable@vger.kernel.org
+Signed-off-by: Max Kellermann <max.kellermann@ionos.com>
+Signed-off-by: David Howells <dhowells@redhat.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ fs/netfs/read_pgpriv2.c | 5 +++--
+ 1 file changed, 3 insertions(+), 2 deletions(-)
+
+--- a/fs/netfs/read_pgpriv2.c
++++ b/fs/netfs/read_pgpriv2.c
+@@ -181,16 +181,17 @@ void netfs_pgpriv2_write_to_the_cache(st
+ break;
+
+ folioq_unmark3(folioq, slot);
+- if (!folioq->marks3) {
++ while (!folioq->marks3) {
+ folioq = folioq->next;
+ if (!folioq)
+- break;
++ goto end_of_queue;
+ }
+
+ slot = __ffs(folioq->marks3);
+ folio = folioq_folio(folioq, slot);
+ }
+
++end_of_queue:
+ netfs_issue_write(wreq, &wreq->io_streams[1]);
+ smp_wmb(); /* Write lists before ALL_QUEUED. */
+ set_bit(NETFS_RREQ_ALL_QUEUED, &wreq->flags);
projects / thirdparty / kernel / stable-queue.git / commitdiff
