From 72b5322f11ff0abf6a52b3007486656578d2c982 Mon Sep 17 00:00:00 2001 From: Lai Jiangshan Date: Mon, 3 Jun 2013 17:17:15 +0800 Subject: [PATCH] clk: remove notifier from list before freeing it MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The @cn is stay in @clk_notifier_list after it is freed, it cause memory corruption. Example, if @clk is registered(first), unregistered(first), registered(second), unregistered(second). The freed @cn will be used when @clk is registered(second), and the bug will be happened when @clk is unregistered(second): [ 517.040000] clk_notif_dbg clk_notif_dbg.1: clk_notifier_unregister() [ 517.040000] Unable to handle kernel paging request at virtual address 00df3008 [ 517.050000] pgd = ed858000 [ 517.050000] [00df3008] *pgd=00000000 [ 517.060000] Internal error: Oops: 5 [#1] PREEMPT SMP ARM [ 517.060000] Modules linked in: clk_notif_dbg(O-) [last unloaded: clk_notif_dbg] [ 517.060000] CPU: 1 PID: 499 Comm: modprobe Tainted: G O 3.10.0-rc3-00119-ga93cb29-dirty #85 [ 517.060000] task: ee1e0180 ti: ee3e6000 task.ti: ee3e6000 [ 517.060000] PC is at srcu_readers_seq_idx+0x48/0x84 [ 517.060000] LR is at srcu_readers_seq_idx+0x60/0x84 [ 517.060000] pc : [] lr : [] psr: 80070013 [ 517.060000] sp : ee3e7d48 ip : 00000000 fp : ee3e7d6c [ 517.060000] r10: 00000000 r9 : ee3e6000 r8 : 00000000 [ 517.060000] r7 : ed84fe4c r6 : c068ec90 r5 : c068e430 r4 : 00000000 [ 517.060000] r3 : 00df3000 r2 : 00000000 r1 : 00000002 r0 : 00000000 [ 517.060000] Flags: Nzcv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user [ 517.060000] Control: 18c5387d Table: 2d85804a DAC: 00000015 [ 517.060000] Process modprobe (pid: 499, stack limit = 0xee3e6238) [ 517.060000] Stack: (0xee3e7d48 to 0xee3e8000) .... [ 517.060000] [] (srcu_readers_seq_idx+0x48/0x84) from [] (try_check_zero+0x34/0xfc) [ 517.060000] [] (try_check_zero+0x34/0xfc) from [] (srcu_advance_batches+0x58/0x114) [ 517.060000] [] (srcu_advance_batches+0x58/0x114) from [] (__synchronize_srcu+0x114/0x1ac) [ 517.060000] [] (__synchronize_srcu+0x114/0x1ac) from [] (synchronize_srcu+0x2c/0x34) [ 517.060000] [] (synchronize_srcu+0x2c/0x34) from [] (srcu_notifier_chain_unregister+0x68/0x74) [ 517.060000] [] (srcu_notifier_chain_unregister+0x68/0x74) from [] (clk_notifier_unregister+0x7c/0xc0) [ 517.060000] [] (clk_notifier_unregister+0x7c/0xc0) from [] (clk_notif_dbg_remove+0x34/0x9c [clk_notif_dbg]) [ 517.060000] [] (clk_notif_dbg_remove+0x34/0x9c [clk_notif_dbg]) from [] (platform_drv_remove+0x24/0x28) [ 517.060000] [] (platform_drv_remove+0x24/0x28) from [] (__device_release_driver+0x8c/0xd4) [ 517.060000] [] (__device_release_driver+0x8c/0xd4) from [] (driver_detach+0x9c/0xc4) [ 517.060000] [] (driver_detach+0x9c/0xc4) from [] (bus_remove_driver+0xcc/0xfc) [ 517.060000] [] (bus_remove_driver+0xcc/0xfc) from [] (driver_unregister+0x54/0x78) [ 517.060000] [] (driver_unregister+0x54/0x78) from [] (platform_driver_unregister+0x1c/0x20) [ 517.060000] [] (platform_driver_unregister+0x1c/0x20) from [] (clk_notif_dbg_driver_exit+0x14/0x1c [clk_notif_dbg]) [ 517.060000] [] (clk_notif_dbg_driver_exit+0x14/0x1c [clk_notif_dbg]) from [] (SyS_delete_module+0x200/0x28c) [ 517.060000] [] (SyS_delete_module+0x200/0x28c) from [] (ret_fast_syscall+0x0/0x48) [ 517.060000] Code: e5973004 e7911102 e0833001 e2881002 (e7933101) Cc: stable@kernel.org Reported-by: Sören Brinkmann Signed-off-by: Lai Jiangshan Tested-by: Sören Brinkmann Signed-off-by: Mike Turquette [mturquette@linaro.org: shortened $SUBJECT] --- drivers/clk/clk.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index 934cfd18f72ded..1144e8c7579ddd 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -1955,6 +1955,7 @@ int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb) /* XXX the notifier code should handle this better */ if (!cn->notifier_head.head) { srcu_cleanup_notifier_head(&cn->notifier_head); + list_del(&cn->node); kfree(cn); }