From 3abcedfdfd3125431ed404fa75724118beac630b Mon Sep 17 00:00:00 2001 From: Shay Drory Date: Mon, 4 May 2026 21:02:03 +0300 Subject: [PATCH 1/4] net/mlx5: SD: Serialize init/cleanup mlx5_sd_init() / mlx5_sd_cleanup() may run from multiple PFs in the same Socket-Direct group. This can cause the SD bring-up/tear-down sequence to be executed more than once or interleaved across PFs. Protect SD init/cleanup with mlx5_devcom_comp_lock() and track the SD group state on the primary device. Skip init if the primary is already UP, and skip cleanup unless the primary is UP. The state check on cleanup is needed because sd_register() drops the devcom comp lock between marking the comp ready and assigning primary_dev on each peer. A concurrent cleanup that acquires the lock in this window would observe devcom_is_ready==true while primary_dev is still NULL (causing mlx5_sd_get_primary() to return NULL) or while the FW alias setup performed by mlx5_sd_init()'s body has not yet run (causing sd_cmd_unset_primary() to dereference a NULL tx_ft). Gate the cleanup body on primary_sd->state == MLX5_SD_STATE_UP, which is set only at the very end of mlx5_sd_init() under the same comp lock - so observing UP guarantees primary_dev, secondaries[], tx_ft, and dfs are all populated. Also bail explicitly if mlx5_sd_get_primary() returns NULL, in case state is checked on a peer whose primary_dev hasn't been assigned yet. In addition, move mlx5_devcom_comp_set_ready(false) from sd_unregister() into the cleanup's locked section, including the !primary and state != UP early-exit paths, so the device cannot unregister and free its struct mlx5_sd while devcom is still marked ready. A concurrent init acquiring the devcom lock will now observe devcom is no longer ready and bail out immediately. Fixes: 381978d28317 ("net/mlx5e: Create single netdev per SD group") Signed-off-by: Shay Drory Signed-off-by: Tariq Toukan Link: https://patch.msgid.link/20260504180206.268568-2-tariqt@nvidia.com Signed-off-by: Jakub Kicinski --- .../net/ethernet/mellanox/mlx5/core/lib/sd.c | 56 +++++++++++++++++-- 1 file changed, 50 insertions(+), 6 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lib/sd.c b/drivers/net/ethernet/mellanox/mlx5/core/lib/sd.c index 762c783156b4..ec42685bdece 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/lib/sd.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/lib/sd.c @@ -18,6 +18,7 @@ struct mlx5_sd { u8 host_buses; struct mlx5_devcom_comp_dev *devcom; struct dentry *dfs; + u8 state; bool primary; union { struct { /* primary */ @@ -31,6 +32,11 @@ struct mlx5_sd { }; }; +enum mlx5_sd_state { + MLX5_SD_STATE_DOWN = 0, + MLX5_SD_STATE_UP, +}; + static int mlx5_sd_get_host_buses(struct mlx5_core_dev *dev) { struct mlx5_sd *sd = mlx5_get_sd(dev); @@ -270,9 +276,6 @@ static void sd_unregister(struct mlx5_core_dev *dev) { struct mlx5_sd *sd = mlx5_get_sd(dev); - mlx5_devcom_comp_lock(sd->devcom); - mlx5_devcom_comp_set_ready(sd->devcom, false); - mlx5_devcom_comp_unlock(sd->devcom); mlx5_devcom_unregister_component(sd->devcom); } @@ -426,6 +429,7 @@ int mlx5_sd_init(struct mlx5_core_dev *dev) struct mlx5_core_dev *primary, *pos, *to; struct mlx5_sd *sd = mlx5_get_sd(dev); u8 alias_key[ACCESS_KEY_LEN]; + struct mlx5_sd *primary_sd; int err, i; err = sd_init(dev); @@ -440,10 +444,17 @@ int mlx5_sd_init(struct mlx5_core_dev *dev) if (err) goto err_sd_cleanup; + mlx5_devcom_comp_lock(sd->devcom); if (!mlx5_devcom_comp_is_ready(sd->devcom)) - return 0; + goto out; primary = mlx5_sd_get_primary(dev); + if (!primary) + goto out; + + primary_sd = mlx5_get_sd(primary); + if (primary_sd->state != MLX5_SD_STATE_DOWN) + goto out; for (i = 0; i < ACCESS_KEY_LEN; i++) alias_key[i] = get_random_u8(); @@ -472,6 +483,9 @@ int mlx5_sd_init(struct mlx5_core_dev *dev) sd->group_id, mlx5_devcom_comp_get_size(sd->devcom)); sd_print_group(primary); + primary_sd->state = MLX5_SD_STATE_UP; +out: + mlx5_devcom_comp_unlock(sd->devcom); return 0; err_unset_secondaries: @@ -481,6 +495,15 @@ int mlx5_sd_init(struct mlx5_core_dev *dev) sd_cmd_unset_primary(primary); debugfs_remove_recursive(sd->dfs); err_sd_unregister: + mlx5_sd_for_each_secondary(i, primary, pos) { + struct mlx5_sd *peer_sd = mlx5_get_sd(pos); + + primary_sd->secondaries[i - 1] = NULL; + peer_sd->primary_dev = NULL; + } + primary_sd->primary = false; + mlx5_devcom_comp_set_ready(sd->devcom, false); + mlx5_devcom_comp_unlock(sd->devcom); sd_unregister(dev); err_sd_cleanup: sd_cleanup(dev); @@ -491,22 +514,43 @@ void mlx5_sd_cleanup(struct mlx5_core_dev *dev) { struct mlx5_sd *sd = mlx5_get_sd(dev); struct mlx5_core_dev *primary, *pos; + struct mlx5_sd *primary_sd; int i; if (!sd) return; + mlx5_devcom_comp_lock(sd->devcom); if (!mlx5_devcom_comp_is_ready(sd->devcom)) - goto out; + goto out_unlock; primary = mlx5_sd_get_primary(dev); + if (!primary) + goto out_ready_false; + + primary_sd = mlx5_get_sd(primary); + if (primary_sd->state != MLX5_SD_STATE_UP) + goto out_clear_peers; + mlx5_sd_for_each_secondary(i, primary, pos) sd_cmd_unset_secondary(pos); sd_cmd_unset_primary(primary); debugfs_remove_recursive(sd->dfs); sd_info(primary, "group id %#x, uncombined\n", sd->group_id); -out: + primary_sd->state = MLX5_SD_STATE_DOWN; +out_clear_peers: + mlx5_sd_for_each_secondary(i, primary, pos) { + struct mlx5_sd *peer_sd = mlx5_get_sd(pos); + + primary_sd->secondaries[i - 1] = NULL; + peer_sd->primary_dev = NULL; + } + primary_sd->primary = false; +out_ready_false: + mlx5_devcom_comp_set_ready(sd->devcom, false); +out_unlock: + mlx5_devcom_comp_unlock(sd->devcom); sd_unregister(dev); sd_cleanup(dev); } From 05217e4ffbb229e7218cf318e0033780abadb624 Mon Sep 17 00:00:00 2001 From: Shay Drory Date: Mon, 4 May 2026 21:02:04 +0300 Subject: [PATCH 2/4] net/mlx5: SD, Keep multi-pf debugfs entries on primary mlx5_sd_init() creates the "multi-pf" debugfs directory under the primary device debugfs root, but stored the dentry in the calling device's sd struct. When sd_cleanup() run on a different PF, this leads to using the wrong sd->dfs for removing entries, which results in memory leak and an error in when re-creating the SD.[1] Fix it by explicitly storing the debugfs dentry in the primary device sd struct and use it for all per-group files. [1] debugfs: 'multi-pf' already exists in '0000:08:00.1' Fixes: 4375130bf527 ("net/mlx5: SD, Add debugfs") Signed-off-by: Shay Drory Signed-off-by: Tariq Toukan Link: https://patch.msgid.link/20260504180206.268568-3-tariqt@nvidia.com Signed-off-by: Jakub Kicinski --- .../net/ethernet/mellanox/mlx5/core/lib/sd.c | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lib/sd.c b/drivers/net/ethernet/mellanox/mlx5/core/lib/sd.c index ec42685bdece..89b7e4d67303 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/lib/sd.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/lib/sd.c @@ -463,9 +463,13 @@ int mlx5_sd_init(struct mlx5_core_dev *dev) if (err) goto err_sd_unregister; - sd->dfs = debugfs_create_dir("multi-pf", mlx5_debugfs_get_dev_root(primary)); - debugfs_create_x32("group_id", 0400, sd->dfs, &sd->group_id); - debugfs_create_file("primary", 0400, sd->dfs, primary, &dev_fops); + primary_sd->dfs = + debugfs_create_dir("multi-pf", + mlx5_debugfs_get_dev_root(primary)); + debugfs_create_x32("group_id", 0400, primary_sd->dfs, + &primary_sd->group_id); + debugfs_create_file("primary", 0400, primary_sd->dfs, primary, + &dev_fops); mlx5_sd_for_each_secondary(i, primary, pos) { char name[32]; @@ -475,7 +479,8 @@ int mlx5_sd_init(struct mlx5_core_dev *dev) goto err_unset_secondaries; snprintf(name, sizeof(name), "secondary_%d", i - 1); - debugfs_create_file(name, 0400, sd->dfs, pos, &dev_fops); + debugfs_create_file(name, 0400, primary_sd->dfs, pos, + &dev_fops); } @@ -493,7 +498,8 @@ int mlx5_sd_init(struct mlx5_core_dev *dev) mlx5_sd_for_each_secondary_to(i, primary, to, pos) sd_cmd_unset_secondary(pos); sd_cmd_unset_primary(primary); - debugfs_remove_recursive(sd->dfs); + debugfs_remove_recursive(primary_sd->dfs); + primary_sd->dfs = NULL; err_sd_unregister: mlx5_sd_for_each_secondary(i, primary, pos) { struct mlx5_sd *peer_sd = mlx5_get_sd(pos); @@ -535,7 +541,8 @@ void mlx5_sd_cleanup(struct mlx5_core_dev *dev) mlx5_sd_for_each_secondary(i, primary, pos) sd_cmd_unset_secondary(pos); sd_cmd_unset_primary(primary); - debugfs_remove_recursive(sd->dfs); + debugfs_remove_recursive(primary_sd->dfs); + primary_sd->dfs = NULL; sd_info(primary, "group id %#x, uncombined\n", sd->group_id); primary_sd->state = MLX5_SD_STATE_DOWN; From 3564222cfdde83a2d760b80192155a3ada1c9bdd Mon Sep 17 00:00:00 2001 From: Shay Drory Date: Mon, 4 May 2026 21:02:05 +0300 Subject: [PATCH 3/4] net/mlx5e: SD, Fix missing cleanup on probe error When _mlx5e_probe() fails, the preceding successful mlx5_sd_init() is not undone. Auxiliary bus probe failure skips binding, so mlx5e_remove() is never called for that adev and the matching mlx5_sd_cleanup() never runs - leaking the per-dev SD struct. Call mlx5_sd_cleanup() on the probe error path to balance mlx5_sd_init(). A similar gap exists on the resume path: mlx5_sd_init() and mlx5_sd_cleanup() are currently bundled with both probe/remove and suspend/resume, even though only the FW alias state actually needs to follow the suspend/resume lifecycle - the sd struct allocation and devcom membership are software state that should track the full bound lifetime. As a result, a failed resume can leave a still-bound device with sd == NULL, which mlx5_sd_get_adev() can't distinguish from a non-SD device. Fixing this requires sd_suspend/resume APIs which will only destroy FW resources and is left for a follow-up series. Fixes: 381978d28317 ("net/mlx5e: Create single netdev per SD group") Signed-off-by: Shay Drory Signed-off-by: Tariq Toukan Link: https://patch.msgid.link/20260504180206.268568-4-tariqt@nvidia.com Signed-off-by: Jakub Kicinski --- drivers/net/ethernet/mellanox/mlx5/core/en_main.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c index 8e9443caa933..62b70334a13d 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c @@ -6775,8 +6775,8 @@ static int mlx5e_resume(struct auxiliary_device *adev) actual_adev = mlx5_sd_get_adev(mdev, adev, edev->idx); if (actual_adev) - return _mlx5e_resume(actual_adev); - return 0; + err = _mlx5e_resume(actual_adev); + return err; } static int _mlx5e_suspend(struct auxiliary_device *adev, bool pre_netdev_reg) @@ -6912,9 +6912,16 @@ static int mlx5e_probe(struct auxiliary_device *adev, return err; actual_adev = mlx5_sd_get_adev(mdev, adev, edev->idx); - if (actual_adev) - return _mlx5e_probe(actual_adev); + if (actual_adev) { + err = _mlx5e_probe(actual_adev); + if (err) + goto sd_cleanup; + } return 0; + +sd_cleanup: + mlx5_sd_cleanup(mdev); + return err; } static void _mlx5e_remove(struct auxiliary_device *adev) From d466ddda5500b6b8ae060909d2317811f2c32a6a Mon Sep 17 00:00:00 2001 From: Shay Drory Date: Mon, 4 May 2026 21:02:06 +0300 Subject: [PATCH 4/4] net/mlx5e: SD, Fix race condition in secondary device probe/remove When utilizing Socket-Direct single netdev functionality the driver resolves the actual auxiliary device using mlx5_sd_get_adev(). However, the current implementation returns the primary ETH auxiliary device without holding the device lock, leading to a potential race condition where the ETH device could be unbound or removed concurrently during probe, suspend, resume, or remove operations.[1] Fix this by introducing mlx5_sd_put_adev() and updating mlx5_sd_get_adev() so that secondaries devices would get a ref and acquire the device lock of the returned auxiliary device. After the lock is acquired, a second devcom check is needed[2]. In addition, update The callers to pair the get operation with the new put operation, ensuring the lock is held while the auxiliary device is being operated on and released afterwards. The "primary" designation is determined once in sd_register(). It's set before devcom is marked ready, and it never changes after that. In Addition, The primary path never locks a secondary: When the primary device invoke mlx5_sd_get_adev(), it sees dev == primary and returns. no additional lock is taken. Therefore lock ordering is always: secondary_lock -> primary_lock. The reverse never happens, so ABBA deadlock is impossible. [1] for example: BUG: kernel NULL pointer dereference, address: 0000000000000370 PGD 0 P4D 0 Oops: Oops: 0000 [#1] SMP CPU: 4 UID: 0 PID: 3945 Comm: bash Not tainted 6.19.0-rc3+ #1 NONE Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 RIP: 0010:mlx5e_dcbnl_dscp_app+0x23/0x100 [mlx5_core] Call Trace: mlx5e_remove+0x82/0x12a [mlx5_core] device_release_driver_internal+0x194/0x1f0 bus_remove_device+0xc6/0x140 device_del+0x159/0x3c0 ? devl_param_driverinit_value_get+0x29/0x80 mlx5_rescan_drivers_locked+0x92/0x160 [mlx5_core] mlx5_unregister_device+0x34/0x50 [mlx5_core] mlx5_uninit_one+0x43/0xb0 [mlx5_core] remove_one+0x4e/0xc0 [mlx5_core] pci_device_remove+0x39/0xa0 device_release_driver_internal+0x194/0x1f0 unbind_store+0x99/0xa0 kernfs_fop_write_iter+0x12e/0x1e0 vfs_write+0x215/0x3d0 ksys_write+0x5f/0xd0 do_syscall_64+0x55/0xe90 entry_SYSCALL_64_after_hwframe+0x4b/0x53 [2] CPU0 (primary) CPU1 (secondary) ========================================================================== mlx5e_remove() (device_lock held) mlx5e_remove() (2nd device_lock held) mlx5_sd_get_adev() mlx5_devcom_comp_is_ready() => true device_lock(primary) mlx5_sd_get_adev() ==> ret adev _mlx5e_remove() mlx5_sd_cleanup() // mlx5e_remove finished // releasing device_lock //need another check here... mlx5_devcom_comp_is_ready() => false Fixes: 381978d28317 ("net/mlx5e: Create single netdev per SD group") Signed-off-by: Shay Drory Signed-off-by: Tariq Toukan Link: https://patch.msgid.link/20260504180206.268568-5-tariqt@nvidia.com Signed-off-by: Jakub Kicinski --- .../net/ethernet/mellanox/mlx5/core/en_main.c | 11 +++++- .../net/ethernet/mellanox/mlx5/core/lib/sd.c | 39 +++++++++++++++++-- .../net/ethernet/mellanox/mlx5/core/lib/sd.h | 2 + 3 files changed, 48 insertions(+), 4 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c index 62b70334a13d..8f2b3abe0092 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c @@ -6774,8 +6774,10 @@ static int mlx5e_resume(struct auxiliary_device *adev) return err; actual_adev = mlx5_sd_get_adev(mdev, adev, edev->idx); - if (actual_adev) + if (actual_adev) { err = _mlx5e_resume(actual_adev); + mlx5_sd_put_adev(actual_adev, adev); + } return err; } @@ -6815,6 +6817,8 @@ static int mlx5e_suspend(struct auxiliary_device *adev, pm_message_t state) err = _mlx5e_suspend(actual_adev, false); mlx5_sd_cleanup(mdev); + if (actual_adev) + mlx5_sd_put_adev(actual_adev, adev); return err; } @@ -6916,11 +6920,14 @@ static int mlx5e_probe(struct auxiliary_device *adev, err = _mlx5e_probe(actual_adev); if (err) goto sd_cleanup; + mlx5_sd_put_adev(actual_adev, adev); } return 0; sd_cleanup: mlx5_sd_cleanup(mdev); + if (actual_adev) + mlx5_sd_put_adev(actual_adev, adev); return err; } @@ -6973,6 +6980,8 @@ static void mlx5e_remove(struct auxiliary_device *adev) _mlx5e_remove(actual_adev); mlx5_sd_cleanup(mdev); + if (actual_adev) + mlx5_sd_put_adev(actual_adev, adev); } static const struct auxiliary_device_id mlx5e_id_table[] = { diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lib/sd.c b/drivers/net/ethernet/mellanox/mlx5/core/lib/sd.c index 89b7e4d67303..6e199161b008 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/lib/sd.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/lib/sd.c @@ -562,22 +562,55 @@ void mlx5_sd_cleanup(struct mlx5_core_dev *dev) sd_cleanup(dev); } +/* Lock order: + * primary: actual_adev_lock -> SD devcom comp lock + * secondary: SD devcom comp lock -> (drop) -> actual_adev_lock + * The two locks are never held together, so no ABBA. + */ struct auxiliary_device *mlx5_sd_get_adev(struct mlx5_core_dev *dev, struct auxiliary_device *adev, int idx) { struct mlx5_sd *sd = mlx5_get_sd(dev); struct mlx5_core_dev *primary; + struct mlx5_adev *primary_adev; if (!sd) return adev; - if (!mlx5_devcom_comp_is_ready(sd->devcom)) + mlx5_devcom_comp_lock(sd->devcom); + if (!mlx5_devcom_comp_is_ready(sd->devcom)) { + mlx5_devcom_comp_unlock(sd->devcom); return NULL; + } primary = mlx5_sd_get_primary(dev); - if (dev == primary) + if (!primary || dev == primary) { + mlx5_devcom_comp_unlock(sd->devcom); return adev; + } - return &primary->priv.adev[idx]->adev; + primary_adev = primary->priv.adev[idx]; + get_device(&primary_adev->adev.dev); + mlx5_devcom_comp_unlock(sd->devcom); + + device_lock(&primary_adev->adev.dev); + /* Primary may have completed remove between dropping devcom and + * acquiring device_lock; recheck. + */ + if (!mlx5_devcom_comp_is_ready(sd->devcom)) { + device_unlock(&primary_adev->adev.dev); + put_device(&primary_adev->adev.dev); + return NULL; + } + return &primary_adev->adev; +} + +void mlx5_sd_put_adev(struct auxiliary_device *actual_adev, + struct auxiliary_device *adev) +{ + if (actual_adev != adev) { + device_unlock(&actual_adev->dev); + put_device(&actual_adev->dev); + } } diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lib/sd.h b/drivers/net/ethernet/mellanox/mlx5/core/lib/sd.h index 137efaf9aabc..9bfd5b9756b5 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/lib/sd.h +++ b/drivers/net/ethernet/mellanox/mlx5/core/lib/sd.h @@ -15,6 +15,8 @@ struct mlx5_core_dev *mlx5_sd_ch_ix_get_dev(struct mlx5_core_dev *primary, int c struct auxiliary_device *mlx5_sd_get_adev(struct mlx5_core_dev *dev, struct auxiliary_device *adev, int idx); +void mlx5_sd_put_adev(struct auxiliary_device *actual_adev, + struct auxiliary_device *adev); int mlx5_sd_init(struct mlx5_core_dev *dev); void mlx5_sd_cleanup(struct mlx5_core_dev *dev);