| Message ID | 20240613161045.29606-10-kabel@kernel.org (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Updates for turris-mox-rwtm driver | expand |
On Thu, Jun 13, 2024 at 6:11 PM Marek Behún <kabel@kernel.org> wrote: > > Simplify debugfs code: do not check for errors, as debugfs errors should > be ignored, and use devm action for dropping the debugfs directory. ... > -static void rwtm_unregister_debugfs(struct mox_rwtm *rwtm) > +static void rwtm_register_debugfs(struct mox_rwtm *rwtm) > { > - debugfs_remove_recursive(rwtm->debugfs_root); > + struct dentry *root; > + > + root = debugfs_create_dir("turris-mox-rwtm", NULL); > + > + devm_add_action_or_reset(rwtm->dev, rwtm_debugfs_release, root); This is incorrect. If devm_add_action() fails, the root will be removed... > + debugfs_create_file_unsafe("do_sign", 0600, root, rwtm, &do_sign_fops); ...and this most likely will use the dangling pointer. > }
On Thu, 13 Jun 2024 22:37:39 +0200 Andy Shevchenko <andy.shevchenko@gmail.com> wrote: > On Thu, Jun 13, 2024 at 6:11 PM Marek Behún <kabel@kernel.org> wrote: > > > > Simplify debugfs code: do not check for errors, as debugfs errors should > > be ignored, and use devm action for dropping the debugfs directory. > > ... > > > -static void rwtm_unregister_debugfs(struct mox_rwtm *rwtm) > > +static void rwtm_register_debugfs(struct mox_rwtm *rwtm) > > { > > - debugfs_remove_recursive(rwtm->debugfs_root); > > + struct dentry *root; > > + > > + root = debugfs_create_dir("turris-mox-rwtm", NULL); > > + > > + devm_add_action_or_reset(rwtm->dev, rwtm_debugfs_release, root); > > This is incorrect. If devm_add_action() fails, the root will be removed... > > > + debugfs_create_file_unsafe("do_sign", 0600, root, rwtm, &do_sign_fops); > > ...and this most likely will use the dangling pointer. OK, I will first creae the file and then add the action.
diff --git a/drivers/firmware/turris-mox-rwtm.c b/drivers/firmware/turris-mox-rwtm.c index d17dc0679439..a536c9c461a7 100644 --- a/drivers/firmware/turris-mox-rwtm.c +++ b/drivers/firmware/turris-mox-rwtm.c @@ -90,7 +90,6 @@ struct mox_rwtm { * It should be rewritten via crypto API once akcipher API is available * from userspace. */ - struct dentry *debugfs_root; u32 last_sig[MOX_ECC_SIGNATURE_WORDS]; bool last_sig_done; #endif @@ -405,39 +404,23 @@ static const struct file_operations do_sign_fops = { .llseek = no_llseek, }; -static int rwtm_register_debugfs(struct mox_rwtm *rwtm) +static void rwtm_debugfs_release(void *root) { - struct dentry *root, *entry; - - root = debugfs_create_dir("turris-mox-rwtm", NULL); - - if (IS_ERR(root)) - return PTR_ERR(root); - - entry = debugfs_create_file_unsafe("do_sign", 0600, root, rwtm, - &do_sign_fops); - if (IS_ERR(entry)) - goto err_remove; - - rwtm->debugfs_root = root; - - return 0; -err_remove: debugfs_remove_recursive(root); - return PTR_ERR(entry); } -static void rwtm_unregister_debugfs(struct mox_rwtm *rwtm) +static void rwtm_register_debugfs(struct mox_rwtm *rwtm) { - debugfs_remove_recursive(rwtm->debugfs_root); + struct dentry *root; + + root = debugfs_create_dir("turris-mox-rwtm", NULL); + + devm_add_action_or_reset(rwtm->dev, rwtm_debugfs_release, root); + + debugfs_create_file_unsafe("do_sign", 0600, root, rwtm, &do_sign_fops); } #else -static inline int rwtm_register_debugfs(struct mox_rwtm *rwtm) -{ - return 0; -} - -static inline void rwtm_unregister_debugfs(struct mox_rwtm *rwtm) +static inline void rwtm_register_debugfs(struct mox_rwtm *rwtm) { } #endif @@ -502,11 +485,7 @@ static int turris_mox_rwtm_probe(struct platform_device *pdev) goto free_channel; } - ret = rwtm_register_debugfs(rwtm); - if (ret < 0) { - dev_err(dev, "Failed creating debugfs entries: %i\n", ret); - goto free_channel; - } + rwtm_register_debugfs(rwtm); dev_info(dev, "HWRNG successfully registered\n"); @@ -529,7 +508,6 @@ static void turris_mox_rwtm_remove(struct platform_device *pdev) { struct mox_rwtm *rwtm = platform_get_drvdata(pdev); - rwtm_unregister_debugfs(rwtm); mbox_free_channel(rwtm->mbox); }
Simplify debugfs code: do not check for errors, as debugfs errors should be ignored, and use devm action for dropping the debugfs directory. Signed-off-by: Marek Behún <kabel@kernel.org> --- drivers/firmware/turris-mox-rwtm.c | 44 ++++++++---------------------- 1 file changed, 11 insertions(+), 33 deletions(-)