diff mbox series

[net,4/6] lib: objagg: Fix general protection fault

Message ID 3de2a4e3a61b58f948b3fd3b0f0763fabcd9a819.1717684365.git.petrm@nvidia.com (mailing list archive)
State Accepted
Commit b4a3a89fffcdf09702b1f161b914e52abca1894d
Delegated to: Netdev Maintainers
Headers show
Series mlxsw: ACL fixes | expand

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Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag present in non-next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 900 this patch: 900
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers warning 1 maintainers not CCed: akpm@linux-foundation.org
netdev/build_clang success Errors and warnings before: 904 this patch: 904
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 904 this patch: 904
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 9 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 8 this patch: 8
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2024-06-07--09-00 (tests: 1041)

Commit Message

Petr Machata June 6, 2024, 2:49 p.m. UTC 
From: Ido Schimmel <idosch@nvidia.com>

The library supports aggregation of objects into other objects only if
the parent object does not have a parent itself. That is, nesting is not
supported.

Aggregation happens in two cases: Without and with hints, where hints
are a pre-computed recommendation on how to aggregate the provided
objects.

Nesting is not possible in the first case due to a check that prevents
it, but in the second case there is no check because the assumption is
that nesting cannot happen when creating objects based on hints. The
violation of this assumption leads to various warnings and eventually to
a general protection fault [1].

Before fixing the root cause, error out when nesting happens and warn.

[1]
general protection fault, probably for non-canonical address 0xdead000000000d90: 0000 [#1] PREEMPT SMP PTI
CPU: 1 PID: 1083 Comm: kworker/1:9 Tainted: G        W          6.9.0-rc6-custom-gd9b4f1cca7fb #7
Hardware name: Mellanox Technologies Ltd. MSN3700/VMOD0005, BIOS 5.11 01/06/2019
Workqueue: mlxsw_core mlxsw_sp_acl_tcam_vregion_rehash_work
RIP: 0010:mlxsw_sp_acl_erp_bf_insert+0x25/0x80
[...]
Call Trace:
 <TASK>
 mlxsw_sp_acl_atcam_entry_add+0x256/0x3c0
 mlxsw_sp_acl_tcam_entry_create+0x5e/0xa0
 mlxsw_sp_acl_tcam_vchunk_migrate_one+0x16b/0x270
 mlxsw_sp_acl_tcam_vregion_rehash_work+0xbe/0x510
 process_one_work+0x151/0x370
 worker_thread+0x2cb/0x3e0
 kthread+0xd0/0x100
 ret_from_fork+0x34/0x50
 ret_from_fork_asm+0x1a/0x30
 </TASK>

Fixes: 9069a3817d82 ("lib: objagg: implement optimization hints assembly and use hints for object creation")
Reported-by: Alexander Zubkov <green@qrator.net>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Amit Cohen <amcohen@nvidia.com>
Tested-by: Alexander Zubkov <green@qrator.net>
Signed-off-by: Petr Machata <petrm@nvidia.com>
---
 lib/objagg.c | 3 +++
 1 file changed, 3 insertions(+)

Comments

Simon Horman June 8, 2024, 9:01 a.m. UTC | #1 
On Thu, Jun 06, 2024 at 04:49:41PM +0200, Petr Machata wrote:
> From: Ido Schimmel <idosch@nvidia.com>
> 
> The library supports aggregation of objects into other objects only if
> the parent object does not have a parent itself. That is, nesting is not
> supported.
> 
> Aggregation happens in two cases: Without and with hints, where hints
> are a pre-computed recommendation on how to aggregate the provided
> objects.
> 
> Nesting is not possible in the first case due to a check that prevents
> it, but in the second case there is no check because the assumption is
> that nesting cannot happen when creating objects based on hints. The
> violation of this assumption leads to various warnings and eventually to
> a general protection fault [1].
> 
> Before fixing the root cause, error out when nesting happens and warn.
> 
> [1]
> general protection fault, probably for non-canonical address 0xdead000000000d90: 0000 [#1] PREEMPT SMP PTI
> CPU: 1 PID: 1083 Comm: kworker/1:9 Tainted: G        W          6.9.0-rc6-custom-gd9b4f1cca7fb #7
> Hardware name: Mellanox Technologies Ltd. MSN3700/VMOD0005, BIOS 5.11 01/06/2019
> Workqueue: mlxsw_core mlxsw_sp_acl_tcam_vregion_rehash_work
> RIP: 0010:mlxsw_sp_acl_erp_bf_insert+0x25/0x80
> [...]
> Call Trace:
>  <TASK>
>  mlxsw_sp_acl_atcam_entry_add+0x256/0x3c0
>  mlxsw_sp_acl_tcam_entry_create+0x5e/0xa0
>  mlxsw_sp_acl_tcam_vchunk_migrate_one+0x16b/0x270
>  mlxsw_sp_acl_tcam_vregion_rehash_work+0xbe/0x510
>  process_one_work+0x151/0x370
>  worker_thread+0x2cb/0x3e0
>  kthread+0xd0/0x100
>  ret_from_fork+0x34/0x50
>  ret_from_fork_asm+0x1a/0x30
>  </TASK>
> 
> Fixes: 9069a3817d82 ("lib: objagg: implement optimization hints assembly and use hints for object creation")
> Reported-by: Alexander Zubkov <green@qrator.net>
> Signed-off-by: Ido Schimmel <idosch@nvidia.com>
> Reviewed-by: Amit Cohen <amcohen@nvidia.com>
> Tested-by: Alexander Zubkov <green@qrator.net>
> Signed-off-by: Petr Machata <petrm@nvidia.com>

Reviewed-by: Simon Horman <horms@kernel.org>
diff mbox series

Patch

diff --git a/lib/objagg.c b/lib/objagg.c
index 955538c90223..0f99ea5f5371 100644
--- a/lib/objagg.c
+++ b/lib/objagg.c
@@ -167,6 +167,9 @@  static int objagg_obj_parent_assign(struct objagg *objagg,
 {
 	void *delta_priv;
 
+	if (WARN_ON(!objagg_obj_is_root(parent)))
+		return -EINVAL;
+
 	delta_priv = objagg->ops->delta_create(objagg->priv, parent->obj,
 					       objagg_obj->obj);
 	if (IS_ERR(delta_priv))