Fix a memory leak in netpoll and introduce netconsole selftests that
expose the issue when running with kmemleak detection enabled.
This patchset includes a selftest for netpoll with multiple concurrent
users (netconsole + bonding), which simulates the scenario from test[1]
that originally demonstrated the issue allegedly fixed by commit
efa95b01da18 ("netpoll: fix use after free") - a commit that is now
being reverted.
Sending this to "net" branch because this is a fix, and the selftest
might help with the backports validation.
Link: https://lore.kernel.org/lkml/96b940137a50e5c387687bb4f57de8b0435a653f.14048… [1]
Signed-off-by: Breno Leitao <leitao(a)debian.org>
---
Changes in v5:
- Set CONFIG_BONDING=m in selftests/drivers/net/config.
- Link to v4: https://lore.kernel.org/r/20250917-netconsole_torture-v4-0-0a5b3b8f81ce@deb…
Changes in v4:
- Added an additional selftest to test multiple netpoll users in
parallel
- Link to v3: https://lore.kernel.org/r/20250905-netconsole_torture-v3-0-875c7febd316@deb…
Changes in v3:
- This patchset is a merge of the fix and the selftest together as
recommended by Jakub.
Changes in v2:
- Reuse the netconsole creation from lib_netcons.sh. Thus, refactoring
the create_dynamic_target() (Jakub)
- Move the "wait" to after all the messages has been sent.
- Link to v1: https://lore.kernel.org/r/20250902-netconsole_torture-v1-1-03c6066598e9@deb…
---
Breno Leitao (4):
net: netpoll: fix incorrect refcount handling causing incorrect cleanup
selftest: netcons: refactor target creation
selftest: netcons: create a torture test
selftest: netcons: add test for netconsole over bonded interfaces
net/core/netpoll.c | 7 +-
tools/testing/selftests/drivers/net/Makefile | 2 +
tools/testing/selftests/drivers/net/config | 1 +
.../selftests/drivers/net/lib/sh/lib_netcons.sh | 197 ++++++++++++++++++---
.../selftests/drivers/net/netcons_over_bonding.sh | 76 ++++++++
.../selftests/drivers/net/netcons_torture.sh | 127 +++++++++++++
6 files changed, 385 insertions(+), 25 deletions(-)
---
base-commit: 5e87fdc37f8dc619549d49ba5c951b369ce7c136
change-id: 20250902-netconsole_torture-8fc23f0aca99
Best regards,
--
Breno Leitao <leitao(a)debian.org>
Calling intotify_show_fdinfo() on fd watching an overlayfs inode, while
the overlayfs is being unmounted, can lead to dereferencing NULL ptr.
This issue was found by syzkaller.
Race Condition Diagram:
Thread 1 Thread 2
-------- --------
generic_shutdown_super()
shrink_dcache_for_umount
sb->s_root = NULL
|
| vfs_read()
| inotify_fdinfo()
| * inode get from mark *
| show_mark_fhandle(m, inode)
| exportfs_encode_fid(inode, ..)
| ovl_encode_fh(inode, ..)
| ovl_check_encode_origin(inode)
| * deref i_sb->s_root *
|
|
v
fsnotify_sb_delete(sb)
Which then leads to:
[ 32.133461] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000006: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN NOPTI
[ 32.134438] KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037]
[ 32.135032] CPU: 1 UID: 0 PID: 4468 Comm: systemd-coredum Not tainted 6.17.0-rc6 #22 PREEMPT(none)
<snip registers, unreliable trace>
[ 32.143353] Call Trace:
[ 32.143732] ovl_encode_fh+0xd5/0x170
[ 32.144031] exportfs_encode_inode_fh+0x12f/0x300
[ 32.144425] show_mark_fhandle+0xbe/0x1f0
[ 32.145805] inotify_fdinfo+0x226/0x2d0
[ 32.146442] inotify_show_fdinfo+0x1c5/0x350
[ 32.147168] seq_show+0x530/0x6f0
[ 32.147449] seq_read_iter+0x503/0x12a0
[ 32.148419] seq_read+0x31f/0x410
[ 32.150714] vfs_read+0x1f0/0x9e0
[ 32.152297] ksys_read+0x125/0x240
IOW ovl_check_encode_origin derefs inode->i_sb->s_root, after it was set
to NULL in the unmount path.
Minimize the window of opportunity by adding explicit check.
Fixes: c45beebfde34 ("ovl: support encoding fid from inode with no alias")
Signed-off-by: Jakub Acs <acsjakub(a)amazon.de>
Cc: Miklos Szeredi <miklos(a)szeredi.hu>
Cc: Amir Goldstein <amir73il(a)gmail.com>
Cc: linux-unionfs(a)vger.kernel.org
Cc: linux-kernel(a)vger.kernel.org
Cc: stable(a)vger.kernel.org
---
I'm happy to take suggestions for a better fix - I looked at taking
s_umount for reading, but it wasn't clear to me for how long would the
fdinfo path need to hold it. Hence the most primitive suggestion in this
v1.
I'm also not sure if ENOENT or EBUSY is better?.. or even something else?
fs/overlayfs/export.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/fs/overlayfs/export.c b/fs/overlayfs/export.c
index 83f80fdb1567..424c73188e06 100644
--- a/fs/overlayfs/export.c
+++ b/fs/overlayfs/export.c
@@ -195,6 +195,8 @@ static int ovl_check_encode_origin(struct inode *inode)
if (!ovl_inode_lower(inode))
return 0;
+ if (!inode->i_sb->s_root)
+ return -ENOENT;
/*
* Root is never indexed, so if there's an upper layer, encode upper for
* root.
--
2.47.3
Amazon Web Services Development Center Germany GmbH
Tamara-Danz-Str. 13
10243 Berlin
Geschaeftsfuehrung: Christian Schlaeger, Jonathan Weiss
Eingetragen am Amtsgericht Charlottenburg unter HRB 257764 B
Sitz: Berlin
Ust-ID: DE 365 538 597
We were copying the bo content the bos on the list
"xe->pinned.late.kernel_bo_present" twice on suspend.
Presumingly the intent is to copy the pinned external bos on
the first pass.
This is harmless since we (currently) should have no pinned
external bos needing copy since
a) exernal system bos don't have compressed content,
b) We do not (yet) allow pinning of VRAM bos.
Still, fix this up so that we copy pinned external bos on
the first pass. We're about to allow bos pinned in VRAM.
Fixes: c6a4d46ec1d7 ("drm/xe: evict user memory in PM notifier")
Cc: Matthew Auld <matthew.auld(a)intel.com>
Cc: <stable(a)vger.kernel.org> # v6.16+
Signed-off-by: Thomas Hellström <thomas.hellstrom(a)linux.intel.com>
---
drivers/gpu/drm/xe/xe_bo_evict.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/xe/xe_bo_evict.c b/drivers/gpu/drm/xe/xe_bo_evict.c
index 7484ce55a303..d5dbc51e8612 100644
--- a/drivers/gpu/drm/xe/xe_bo_evict.c
+++ b/drivers/gpu/drm/xe/xe_bo_evict.c
@@ -158,8 +158,8 @@ int xe_bo_evict_all(struct xe_device *xe)
if (ret)
return ret;
- ret = xe_bo_apply_to_pinned(xe, &xe->pinned.late.kernel_bo_present,
- &xe->pinned.late.evicted, xe_bo_evict_pinned);
+ ret = xe_bo_apply_to_pinned(xe, &xe->pinned.late.external,
+ &xe->pinned.late.external, xe_bo_evict_pinned);
if (!ret)
ret = xe_bo_apply_to_pinned(xe, &xe->pinned.late.kernel_bo_present,
--
2.51.0