4.4-stable review patch. If anyone has any objections, please let me know.
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From: Kamlakant Patel kamlakant.patel@cavium.com
[ Upstream commit f002612b9d86613bc6fde0a444e0095225f6053e ]
This happens when BMC doesn't return any data and the code is trying to print the value of data[2].
Getting following crash: [ 484.728410] Unable to handle kernel NULL pointer dereference at virtual address 00000002 [ 484.736496] pgd = ffff0000094a2000 [ 484.739885] [00000002] *pgd=00000047fcffe003, *pud=00000047fcffd003, *pmd=0000000000000000 [ 484.748158] Internal error: Oops: 96000005 [#1] SMP [...] [ 485.101451] Call trace: [...] [ 485.188473] [<ffff000000a46e68>] msg_done_handler+0x668/0x700 [ipmi_ssif] [ 485.195249] [<ffff000000a456b8>] ipmi_ssif_thread+0x110/0x128 [ipmi_ssif] [ 485.202038] [<ffff0000080f1430>] kthread+0x108/0x138 [ 485.206994] [<ffff0000080838e0>] ret_from_fork+0x10/0x30 [ 485.212294] Code: aa1903e1 aa1803e0 b900227f 95fef6a5 (39400aa3)
Adding a check to validate the data len before printing data[2] to fix this issue.
Signed-off-by: Kamlakant Patel kamlakant.patel@cavium.com Signed-off-by: Corey Minyard cminyard@mvista.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/char/ipmi/ipmi_ssif.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/char/ipmi/ipmi_ssif.c +++ b/drivers/char/ipmi/ipmi_ssif.c @@ -757,7 +757,7 @@ static void msg_done_handler(struct ssif ssif_info->ssif_state = SSIF_NORMAL; ipmi_ssif_unlock_cond(ssif_info, flags); pr_warn(PFX "Error getting flags: %d %d, %x\n", - result, len, data[2]); + result, len, (len >= 3) ? data[2] : 0); } else if (data[0] != (IPMI_NETFN_APP_REQUEST | 1) << 2 || data[1] != IPMI_GET_MSG_FLAGS_CMD) { /* @@ -779,7 +779,7 @@ static void msg_done_handler(struct ssif if ((result < 0) || (len < 3) || (data[2] != 0)) { /* Error clearing flags */ pr_warn(PFX "Error clearing flags: %d %d, %x\n", - result, len, data[2]); + result, len, (len >= 3) ? data[2] : 0); } else if (data[0] != (IPMI_NETFN_APP_REQUEST | 1) << 2 || data[1] != IPMI_CLEAR_MSG_FLAGS_CMD) { pr_warn(PFX "Invalid response clearing flags: %x %x\n",